Resin composition, binder resin for toner and toner

ABSTRACT

The invention is [1] a resin composition comprising a resin obtained by polymerizing cyclopentadiene or the like and a specific styrene resin, [2] a resin composition comprising (a) a polystyrene-type polymer component and (b) a specific petroleum resin-based polymer component, and [3] a toner binder resin for development of an electrostatically charged image comprising (A) a terpene resin or the like and (B) a styrene resin and/or a polyester resin. Further, it is a toner binder resin for development of an electrostatically charged image containing these resin compositions as a main component, and a toner for development of an electrostatically charged image comprising the toner binder resin and a coloring material.

TECHNICAL FIELD

The present invention relates to a toner used to develop anelectrostatic latent image formed in an electrophotographic method, anelectrostatic recording method, an electrostatic printing method and thelike, a binder resin used therein, and a resin composition which is amaterial thereof.

BACKGROUND OF THE INVENTION

In recent years, in order to attain coloration and energy saving in anelectrophotographic copying machine or printer and the like, alow-temperature fixing-type toner has been developed. For achieving thelow-temperature fixing, it is effective to decrease a heat-softeningtemperature of a toner resin. Generally, however, when a heat-softeningtemperature of a resin is decreased, a glass transition temperature ofthe toner is decreased at the same time. Accordingly, so-called tonerblocking by which a toner forms a block in a storage state tends tooccur, for which the fixing temperature cannot be decreased as desired.

In order to meet contradictory requirements of both the low-temperaturefixability and the anti-blocking property, for example, Japanese PatentLaid-Open No. 1,952/1981 proposes a method using a polyester resin ofwhich the fixing temperature is low though the affinity for paper ishigh and the heat-softening temperature and the glass transitiontemperature are high. In this case, although the low-temperaturefixability and the anti-blocking property are improved to some extent,both of the properties are not satisfied enough at the same time.Besides, a polyester resin involves a problem that since it has highcohesive energy density, pulverization becomes difficult in productionof a toner.

Meanwhile, Japanese Patent Laid-Open No. 257,868/1992 proposes a tonerusing a petroleum resin excellent in melting property andlow-temperature fixability. Further, Japanese Patent Laid-Open No.278,658/1996 proposes a toner using a hydrogenated petroleum resin. Inthese toners using the petroleum resin and the hydrogenated petroleumresin, however, the heat-softening temperature is low despite the highglass transition temperature. Accordingly, the low-temperaturefixability is excellent, but the resins themselves are brittle, and itis difficult to use these resins singly as a toner resin. Further,almost all of these petroleum resins are a resin in which an aliphaticunsaturated bond remains in more than 50% of a petroleum resin beforehydrogenation, a resin obtained by polymerizing a C₉ monomer unpurifiedor simply purified and a hydrogenated aromatic petroleum resin having ahydrogenation rate of less than 10%. For this reason, all of theseresins are colored yellow to brown. When these are incorporated inamounts of more than 35% by weight, there is a problem that a binderresin is strongly colored and color reproducibility is notsatisfactorily obtained for coloration and also for monochrome. Further,since an active double bond is oxidized with air and a hydrophilic grouptends to occur, there was also a likelihood that electricity stabilityin storage of a toner becomes poor.

Moreover, some of the petroleum resins used in these documents have ahigh content of a volatile component, and there is a likelihood that anodor is given off by heating in fixation at approximately 150° C. whichis a general fixing temperature. Therefore, there is also a problem thatthe proportion of the petroleum resin cannot be increased to acomposition of more than 35% by weight at which the low-temperaturefixability becomes good.

In addition, Japanese Patent Laid-Open Nos. 274,520/1998, 52,611/1999,52,612/1999, 52,614/1999 and 52,615/1999 propose a binder resin using apetroleum resin good in low-temperature fixability and hue and free froman odor in fixation. These have excellent performance in practical use.However, the petroleum resins are themselves incompatible with apolystyrene resin incorporated to have a binder resin exhibit suitablemechanical strength (the binder resin is not too strong nor brittle).Accordingly, both the components are hardly kneaded with highuniformity, and transparency of the resulting composition is notsatisfactory. When this is applied to a toner for coloration, there is aproblem that color reproducibility of transmitted light is notsatisfactory.

Moreover, the use of a resin composition obtained by incorporating astyrene-acrylic resin or a polyester resin in these petroleum resins hasbeen also proposed. In this case, the low-temperature fixability and thegrindability in the production of a toner were improved, but were notsaid to be satisfactory.

DISCLOSURE OF THE INVENTION

The invention aims to provide a toner excellent in low-temperaturefixability, having mechanical strength capable of enduring practical useas a toner and low environmental dependence in charging a toner, freefrom an odor in fixation and excellent in transparency, a binder resinfor obtaining the toner having such characteristics and a resincomposition which is a material thereof.

The invention includes the following first invention, second inventionand third invention.

That is, the gist of the first invention is as follows.

[1] A resin composition comprising a resin (component A) obtained bypolymerizing at least one monomer selected from cyclopentadiene,dicyclopentadiene and dihydrodicyclopentadiene and a styrene resin(component B) in which a content of a structural unit derived fromstyrene is 70% by weight or more.

[2] A toner binder resin for development of an electrostatically chargedimage using a resin composition comprising a resin (component A)obtained by polymerizing at least one monomer selected fromcyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and astyrene resin (component B) in which a content of a structural unitderived from styrene is 70% by weight or more.

[3] A toner binder resin for development of an electrostatically chargedimage using a resin composition in which component A is a resin obtainedby subjecting at least one monomer selected from cyclopentadiene,dicyclopentadiene and dihydrodicyclopentadiene to cationicpolymerization, heat polymerization or radical polymerization and/or aresin obtained by hydrogenating a part or the whole of a carbon-carbonunsaturated bond and/or an aromatic ring of these copolymers andcomponent B is a styrene resin in which a content of a structural unitderived from styrene is 70% by weight or more and which has aweight-average molecular weight of 15,000 to 1,000,000 and anumber-average molecular weight of 1,400 to 300,000.

[4] A toner binder resin for development of an electrostatically chargedimage using a resin composition in which component A is a copolymerresin obtained by copolymerizing (a) at least one monomer selected fromcyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and (b)at least one aromatic vinyl compound selected from styrene,α-methylstyrene, vinyltoluene, isopropenyltoluene, indene,alkyl-substituted indene, allylbenzene, allyltoluene, tert-butylstyreneand tert-butylallylbenzene and/or a resin obtained by hydrogenating apart or the whole of a carbon-carbon unsaturated bond and/or an aromaticring of these copolymer resins and component B is a styrene resin inwhich a content of a structural unit derived from styrene is 70% byweight or more and which has a weight-average molecular weight of 15,000to 1,000,000 and a number-average molecular weight of 1,400 to 300,000.

[5] A toner binder resin for development of an electrostatically chargedimage using a resin composition in which component A is a copolymerresin obtained by copolymerizing (a) at least one monomer selected fromcyclopentadiene, dicyclopentadiene and dihydrodicyclopentadiene and (c)at least one conjugated diolefin selected from isoprene, butadiene and1,3-pentadiene and/or a resin obtained by hydrogenating a part or thewhole of a carbon-carbon unsaturated bond and/or an aromatic ring ofthese copolymer resins and component B is a styrene resin in which acontent of a structural unit derived from styrene is 70% by weight ormore and which has a weight-average molecular weight of 15,000 to1,000,000 and a number-average molecular weight of 1,400 to 300,000.

[6] The toner binder resin for development of an electrostaticallycharged image as recited in any of [2] to [5], wherein the content[A/(A+B)] of component A is 0.3 to 0.99.

[7] The toner binder resin for development of an electrostaticallycharged image as recited in any of [2] to [5], wherein the content[A/(A+B)] of component A is 0.71 to 0.99.

[8] The toner binder resin for development of an electrostaticallycharged image as recited in any of [2] to [7], which toner binder resinhas brittleness that as a break mark in exerting load according to amicro-Vickers hardness meter on a plate obtained by subjecting the resinto hot press molding and having a thickness of 400 to 450 μm, a visiblecrack having a length of 2 mm or more occurs at most once only in 10tests under load of 300 gf and a visible crack having a length of 2 mmor more occurs at least eight times in 10 tests under load of 1,000 gf.

[9] A toner for development of an electrostatically charged image,containing the binder resin as recited in any of [2] to [8] as a tonerbinder resin for development of an electrostatically charged image.

[10] A toner binder resin for fixation with a heating roll using thetoner binder resin for development of an electrostatically charged imageas recited in any of [2] to [8].

[11] A toner for fixation with a heating roll using the toner fordevelopment of an electrostatically charged image as recited in [9].

Further, the gist of the second invention is as follows.

[1] A resin composition comprising (a) 1 to 99% by weight of apolystyrene-type polymer component and (b) 1 to 99% by weight of apetroleum resin-based polymer component in which when the petroleumresin-based polymer forms a resin composition with the polystyreneresin-type polymer at a weight ratio of 1:1, total light transmissionmeasured according to JIS K 7105 on a film-like molded product of theresin composition having a thickness of 3 mm is 60% or more of aquantity of incident light.

[2] The resin composition as recited in [1], wherein when the petroleumresin-based polymer as component (b) forms a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm is60% or more of a quantity of incident light, and haze measured accordingto JIS K 7105 is 40% or less.

[3] The resin composition as recited in [1] or [2], which comprises (a)10 to 65% by weight of the polystyrene-type polymer component and (b) 35to 90% by weight of the petroleum resin-based polymer component.

[4] The resin composition as recited in [1] or [2], which comprises (a)10 to 49% by weight of the polystyrene-type polymer component and (b) 51to 90% by weight of the petroleum resin-based polymer component.

[5] The resin composition as recited in any of [1] to [4], wherein thepolystyrene-type polymer component (a) is a styrene homopolymer and/or astyrene-unsaturated carboxylic ester copolymer in which a ratio of acontent of a styrene unit to a content of an unsaturated carboxylicester unit is 1.1 or more in terms of a weight ratio.

[6] The resin composition as recited in any of [1] to [5], wherein thepetroleum resin-based polymer component (b) is a petroleum resin-basedpolymer having a softening temperature of 130° C. or less.

[7] The resin composition as recited in any of [1] to [6], wherein thepetroleum resin-based polymer component (b) is an aromatic petroleumresin.

[8] The resin composition as recited in any of [1] to [7], wherein thepetroleum resin-based polymer component (b) is a polymer or a copolymerof one or more selected from the group consisting of vinyltoluene,α-methylstyrene, isopropenyltoluene and indene.

[9] The resin composition as recited in any of [1] to [8], wherein thepetroleum resin-based polymer component (b) is an ester group-containingdicyclopentadiene polymer-based petroleum resin having a saponificationvalue of 10 to 400 mg KOH/g.

[10] The resin composition as recited in any of [1] to [9], wherein thepetroleum resin-based polymer component (b) is a hydroxylgroup-containing dicyclopentadiene polymer-based petroleum resin havinga hydroxyl value of 10 to 400 mg KOH/g.

[11] The resin composition as recited in any of [1] to [10], wherein thepetroleum resin-based polymer component (b) is one in which a part orthe whole of the unsaturated bond and/or the aromatic ring ishydrogenated.

[12] The resin composition as recited in any of [1] to [11], wherein thepetroleum resin-based polymer component (b) is a petroleum resin-basedpolymer having weight loss of 1% by weight or less as measured at 150°C. by thermogravimetry.

[13] The resin composition as recited in any of [1] to [12], wherein thepetroleum resin-based polymer component (b) is a petroleum resin-basedpolymer having a Gardener color number of 3 or less as measured in amolten condition according to JIS K 5400.

[14] The resin composition as recited in any of [1] to [13], wherein thepetroleum resin-based polymer component (b) is a petroleum resin-basedpolymer having a Hazen color number of 250 or less as measured accordingto JIS K 6901.

[15] A toner binder resin for development of an electrostaticallycharged image, containing the resin composition as recited in any of [1]to [14] as a main component.

[16] A toner for development of an electrostatically charged image,comprising 100 parts by weight of the toner binder resin as recited in[15] and 0.1 to 100 parts by weight of a coloring material.

[17] A toner for development of an electrostatically charged image,comprising 100 parts by weight of the toner binder resin as recited in[15], 0.1 to 100 parts by weight of a coloring material and 0.1 to 10parts by weight of a charge control agent.

[18] The toner for development of an electrostatically charged image asrecited in [16] or [17], wherein wax is further added in an amount of0.1 to 10 parts by weight per 100 parts by weight of the toner binderresin.

[19] The toner particles for development of an electrostatically chargedimage as recited in any of [16] to [18], wherein a volume-averageparticle diameter is 5 to 15 μm.

[20] A method for producing the toner particles for development of anelectrostatically charged image as recited in [19], wherein a kneadedproduct of the toner as recited in any of [16] to [18] is ground, andparticles having a volume-average particle diameter of 5 to 15 μm areclassified.

Moreover, the gist of the third invention is as follows.

[1] A toner binder resin for development of an electrostatically chargedimage, containing at least one resin selected from (a) a terpene resin,(b) a rosin resin and (c) a hydrogenated aromatic petroleum resin.

[2] The toner binder resin for development of an electrostaticallycharged image as recited in [1], wherein the content of at least oneresin selected from (a) a terpene resin (b) a rosin resin and (c) ahydrogenated aromatic petroleum resin is 5 to 100% by weight.

[3] A toner binder resin for development of an electrostatically chargedimage, containing (A) at least one resin selected from (a) a terpeneresin, (b) a rosin resin and (c) a hydrogenated aromatic petroleumresin, and (B) a styrene resin and/or a polyester resin.

[4] The toner binder resin for development of an electrostaticallycharged image as recited in [3], wherein the weight ratio ((A)/(B)) ofcomponent (A) and component (B) is 90/10 to 15/85.

[5] The toner binder resin for development of an electrostaticallycharged image as recited in [3] or [4], wherein the styrene resin (B) ispolystyrene and/or a styrene/unsaturated carbonyl compound copolymerresin.

[6] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [5], wherein the terpene resin(a) contains a component derived from at least one selected fromα-pinene, β-pinene and dipentene.

[7] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [6], wherein the terpene resin(a) is a copolymer of a terpene and an aromatic vinyl compound.

[8] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [6], wherein the terpene resin(a) is a copolymer of a terpene and a phenolic compound.

[9] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [8], wherein the terpene resin(a) is one in which a part or the whole of the aliphatic unsaturatedbond and/or the aromatic ring is hydrogenated.

[10] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [9], wherein-the rosin resin(b) is a rosin ester resin.

[11] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [9], wherein the rosin resin(b) is a rosin-modified maleic acid resin.

[12] The toner binder resin for development of an electrostaticallycharged image as recited in [10] or [11], wherein the rosin resin (b) isone in which a part or the whole of the aliphatic unsaturated bondand/or the aromatic ring is hydrogenated.

[13] The toner binder resin for development of an electrostaticallycharged image as recited in any of [1] to [12], wherein the hydrogenatedaromatic petroleum resin (c) is one obtained by hydrogenating a part orthe whole of an aromatic ring in a resin formed by polymerizing orcopolymerizing at least one monomer selected from α-methylstyrene,vinyltoluene, isopropenyltoluene and indene.

[14] A toner for development of an electrostatically charged image,containing the binder resin as recited in any of [1] to [13] as a tonerbinder resin for development of an electrostatically charged image.

[15] A toner binder resin for fixation with a heating roll using thetoner binder resin for development of an electrostatically charged imageas recited in any of [1] to [13].

[16] A toner for fixation with a heating roll using the toner fordevelopment of an electrostatically charged image as recited in [14].

BEST MODE FOR CARRYING OUT THE INVENTION

The mode for carrying out the invention is described below.

I. First Invention

The resin composition of the first invention (hereinafter sometimessimply referred to as “the invention” in this column) is a resincomposition comprising a resin (component A) obtained by polymerizing atleast one monomer selected from cyclopentadiene, dicyclopentadiene anddihydrodicyclopentadiene and a styrene resin (component B) in which acontent of a structural unit derived from styrene is 70% by weight ormore.

As the cyclopentadiene resin used herein as component A of this resincomposition may be a homopolymer of any of cyclopentadiene,dicyclopentadiene and dihydrodicyclopentadiene or a copolymer thereof. Apart or the whole of a carbon-carbon unsaturated bond or an aromaticring present in the polymer or the copolymer may be hydrogenated.

Further, this component A may be a copolymer of (a) at least one monomerselected from cyclopentadiene, dicyclopentadiene anddihydrodicyclopentadiene and (b) at least one aromatic vinyl compoundselected from styrene, α-methylstyrene, vinyltoluene,isopropenyltoluene, indene, alkyl-substituted indene, allylbenzene,allyltoluene, tert-butylstyrene and tert-butylallylbenzene. Stillfurther, this component A may be a copolymer of (a) at least one monomerselected from cyclopentadiene, dicyclopentadiene anddihydrodicyclopentadiene and (c) at least one conjugated diolefinselected from isoprene, butadiene and 1,3-pentadiene. Furthermore, itmay be one obtained by hydrogenating a part or the whole of acarbon-carbon unsaturated bond or an aromatic ring present in thesecopolymers.

With respect to the resin used as component A, especially preferableexamples of the copolymer include a styrene-dicyclopentadiene copolymer[styrene:dicyclopentadiene=90:10 to 0:100 (weight ratio)], anindene-dicyclopentadiene copolymer, an indene-styrene-dicyclopentadienecopolymer (indene; indene, methylindene: styrene; styrene,α-methylstyrene, vinyltoluene, isopropenyltoluene: dicyclopentadiene;dicyclopentadiene, dihydrodicyclopentadiene], a dicyclopentadienepolymer and one obtained by hydrogenating a part or the whole of acarbon-carbon unsaturated bond and/or an aromatic ring present in theseresins.

And, the content of the structural unit based on cyclopentadiene,dicyclopentadiene or dihydrodicyclopentadiene contained in thesecopolymers is preferably 10 to 100% by weight. This is because when thecontent of the structural unit is less than 10% by weight, thelow-temperature fixability sometimes cannot satisfactorily be exhibitedwhen it is used as a toner binder resin.

Further, with respect to the resin used as component A, a resin that isnot hydrogenated and a resin obtained by hydrogenating a part or thewhole of a carbon-carbon unsaturated bond or an aromatic ring present inthe resin can favorably be used. However, when the hydrogenated resin isused, a resin hydrogenated such that a hydrogenation rate; a value of[(bromine value before hydrogenation−bromine value afterhydrogenation)/(bromine value before hydrogenation)]×100 reaches 55% ormore is preferable because when a resin composition is formed usingthis, a product having low environmental dependence in charging a toneris obtained. The bromine value of the resin used as component A can beany value. However, a bromine value of 30 g/100 g or less is preferablefrom the aspect of environmental stability in charging a toner orstability in storage. Further, when the resin is used for color,requirements, for example, its hue and transparency are strict. Thus, aresin obtained by hydrogenation such that this bromine value is 10 g/100g or less or further 5 g/100 or less is preferable.

Moreover, with respect to the resin used as component A in which thearomatic ring is hydrogenated, brittleness of the resin composition orvarious requirements such as compatibility with the resin as componentB, hue, transparency and the like can be met by adjusting ahydrogenation rate; a value of [(content of an aromatic ring beforehydrogenation −content of an aromatic ring after hydrogenation)/(contentof an aromatic ring before hydrogenation)]×100 found from an absorptionpeak intensity at wavenumber of 700 cm⁻¹ in infrared absorption analysisto between 0 and 100%. From the standpoint of compatibility with theresin as component B, it is preferably 90% or less. From the standpointof hue and transparency, it is preferably 10% or more.

Next, as the styrene resin used as component B, a resin in which acontent of the structural unit derived from styrene is 70% by weight ormore is used. A resin having a weight-average molecular weight of 15,000to 1,000,000 and a number-average molecular weight of 1,400 to 300,000is especially preferable.

And, examples of the compound used in copolymerization with styrene inthe styrene resin include aromatic ring-containing vinyl compounds suchas α-methylstyrene, vinyltoluene, isopropenyltoluene, indene,alkyl-substituted indene, allylbenzene, allyltoluene, tert-butylstyrene,tert-butylallylbenzene and the like; α-olefins such as ethylene,propylene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene, 1-deceneand the like; chlorine-substituted ethylenes such as vinyl chloride,vinylidene chloride, 1,2-dichloroethylene, trichloroethylene,tetrachloroethylene and the like; vinyl fluoride, vinylidene fluoride,1,2-difluoroethylene, trifluoroethylene, tetrafluoroethylene and thelike. Further, acrylic compounds such as an acrylic ester, a methacrylicester, acrylonitrile and the like, and compounds having a hydrophilicgroup or a polyvalent vinyl group, such as vinyl acetate, maleic acid,maleic ester, maleic anhydride, butadiene, isoprene and the like canalso be used unless the effects of the invention are impaired.

Regarding the resin as component B, a resin in which a content of astructural unit derived from styrene is 70% by weight or more is used.The reason is that when a resin in which a content is less than 70% byweight is used, it is sometimes difficult to satisfactorily maintain thesuitable brittleness of the resulting resin composition, theenvironmental dependence in charging a toner and the grindability.

With respect to the molecular weight of the resin as component B, whenthe weight-average molecular weight is less than 15,000 or thenumber-average molecular weight is less than 1,400, the resulting resincomposition becomes brittle, and is unsuitable in the use as a tonerbinder resin. And, a resin having the weight-average molecular weightexceeding 1,000,000 or the number-average molecular weight exceeding300,000 sometimes decreases the kneading property with component A andthe grindability of the resulting resin composition.

Next, with respect to the mixing ratio of the resin as component A andthe resin as component B, the content of component A [A/(A+B)] is 0.3 to0.99, further preferably 0.71 to 0.99. In this case, regarding theresins of these components A and B, they may be used either singly or incombination. When the content of component A is less than 0.3 in themixing ratio of both the components, there is a high possibility thatthe low-temperature fixability is decreased. Further, when the contentof this component A exceeds 0.99, the resin composition becomes brittle,and is unsuitable in the use as a toner binder resin. Moreover, when theresin composition is used as a toner binder resin in the range of 0.71to 0.99 as a preferable range of the content of component A, a balanceof properties such as the low-temperature fixability, the grindabilityand the environmental dependence in charging a toner is especially good.

Further, the glass transition temperature of this resin composition ispreferably 50° C. or more, more preferably 60° C. or more. When theglass transition temperature of this resin composition is less than 50°C., a toner produced by using the same tends to cause toner blocking bywhich the toner is agglomerated during the storage thereof.

And, with respect to the heat-softening temperature of this resincomposition, a composition having a heat-softening temperature of 80 to140° C., preferably 100 to 130° C. is favorably used. When theheat-softening temperature is less than 80° C., the toner particles tendto be agglomerated in a equipment before development by a frictionalheat or the like. Moreover, when the heat-softening temperature exceeds140° C., the low-temperature fixability is sometimes insufficient.

In addition, the mechanical strengths of this resin composition are alsoimportant properties in practical use along with the thermal properties.Accordingly, with respect to the resins used as components A and B beingstructural components of the resin composition, as stated above, resinswhich have appropriate mechanical strengths, especially controlledbrittleness by adjusting the molecular weight, the copolymerizationcomposition thereof or the like are preferably used.

The thus-controlled resin composition has brittleness that in amicro-Vickers hardness test using a test piece (thickness 400 to 450 μm)obtained by hot-pressing the resin composition, a visible crack having alength of 2 mm or more occurs at most once only in 10 tests under loadof 300 gf and a visible crack having a length of 2 mm or more occurs atleast eight times in 10 tests under load of 1,000 gf.

When a visible crack having a length of 2 mm or more occurs more thanonce in 10 tests under load of 300 gf or less in the micro-Vickersharness test, the resin composition is brittle, and hot offset tends tooccur. Further, there is a likelihood that the toner is finely dividedand reduced in a developing machine or an image printed is thinned byfriction. And, when a visible crack having a length of 2 mm or moreoccurs less than eight times in 10 tests, the resin composition has toostrong mechanical strengths, and it takes great energy and much time togrind the toner. Further, the low-temperature fixability is likely to bedecreased.

The thus-obtained toner binder resin of the invention is especiallyappropriate as a binder resin of a toner for contact heat pressurefixation with a heating roll.

Next, the toner for development of an electrostatically charged image inthe invention contains one or more of the toner binder resins as a tonerresin. And, the content of the toner binder resin in this toner resin isnot particularly limited. It is usually 1% by weight or more, preferably70% by weight or more. When the content of the toner binder resin isless than 1% by weight, its addition effect is not satisfactory. Whenthe content is 1% by weight or more, the effect is satisfactorilyexhibited. Especially when it is 70% by weight or more, the grindabilityin the production of the toner becomes better.

In the toner of the invention, an elastomer can be used as a toner resinalong with the toner binder resin unless the effects of the inventionare impaired. The combined use of this elastomer improves Theologicalcharacteristics in melting, and an offset generating temperature becomeshigh. This elastomer is not particularly limited, and any of knownelastomers can selectively be used.

As this elastomer, for example, nitrile rubber, ethylene propylenerubber, chloroprene rubber, silicone rubber, fluororubber, ethyleneacrylic rubber, polyester elastomer, epichlorohydrin rubber, acrylicrubber, liquid rubber, polyethylene chloride, butadiene rubber, astyrene-butadiene copolymer, natural rubber, 1,2-polybutadiene, butylrubber, polyethylene chlorosulfonate, polysulfide rubber, urethanerubber, a styrenic thermoplastic elastomer, an olefinic thermoplasticelastomer, a urethane-based thermoplastic elastomer, an ester-basedthermoplastic elastomer, a polyvinyl chloride-based thermoplasticelastomer, butyl rubber-grafted polyethylene, trans-1,4-polyisopreneionomer, a natural rubber-based thermoplastic elastomer and the like areavailable. Of these elastomers, a styrene-butadiene copolymer isespecially preferable. And, these elastomers may be used either singlyor in combination.

Further, when these elastomers are used in combination as the tonerbinder resin, the content of the elastomer based on the total tonerresin is preferably 30% by weight or less. When this content exceeds 30%by weight, there is a possibility that the grindability in the tonerproduction is decreased.

Moreover, in the toner of the invention, wax can be used as a tonerresin along with the toner binder resin. The combined use of the wax canimprove releasability of the toner. This wax is not particularlylimited, and any of known waxes can selectively be used.

Preferable examples of this wax include animal and plant waxes, carnaubawax, candelilla wax, Japan wax, beeswax, mineral wax, petroleum wax,paraffin wax, microcrystalline wax, petrolactam, polyethylene wax,oxidized polyethylene wax, polypropylene wax, oxidized polypropylenewax, higher fatty acid wax, higher fatty acid ester wax, carnauba wax,Fischer-Tropsch wax and the like. Further, as a resin having the sameproperties as wax, a styrene oligomer, an amorphous poly-α-olefin andthe like are preferably used. Of these, Fischer-Tropsch wax and astyrene oligomer are especially preferable. These waxes may be usedeither singly or in combination.

Moreover, when the binder resin of the invention and the wax are used incombination, the content of the wax based on the total toner resin ispreferably 30% by weight or less. When the content exceeds 30% byweight, there is a likelihood that the decrease in glass transitiontemperature is invited to decrease the anti-blocking property.

Further, in the toner of the invention, a known thermoplastic resin canbe used in combination as required. Examples of the thermoplastic resininclude polyester resins [alcohol component; α,ω-alkylene diols (C₂-C₁₂)such as ethylene glycol, diethylene glycol, triethylene glycol,propylene glycol, 1,4-bis(hydroxymethyl)cyclohexane, bisphenol A,bisphenol A-ethylene glycol-modified diol, 1,3-propylene glycol and thelike, hydrogenated bisphenol A, bisphenol F, bisphenol F-ethyleneglycol-modified diol, bisphenol S, bisphenol S-ethylene glycol-modifieddiol, bisphenol, biphenol-ethylene glycol-modified diol, neopentylglycol and trihydric or higher hydric alcohol: carboxylic acidcomponent; aliphatic dicarboxylic acid, alicyclic dicarboxylic acid,aromatic dicarboxylic acid and tribasic or higher basic carboxylicacid], polystyrene, chloropolystyrene, poly-α-methylstyrene,poly-4-methoxystyrene, poly-4-hydroxystyrene, a styrene-chlorostyrenecopolymer, a styrene-propylene copolymer, a styrene-vinyl chloridecopolymer, a styrene-maleic acid copolymer, a styrene-vinyl acetatecopolymer, a styrene-acrylic ester copolymer (methyl, ethyl, butyl,octyl and phenyl esters), a styrene-methacrylic ester copolymer (methyl,ethyl, butyl, octyl and phenyl esters), a styrene-methylα-chloroacrylate copolymer, a styrene-acrylonitrile-acrylic estercopolymer, an α-methylstyrene-acrylic ester copolymer (methyl, ethyl,butyl, octyl and phenyl esters), an α-methylstyrene-methacrylic estercopolymer (methyl, ethyl, butyl, octyl and phenyl esters), anα-methylstyrene-methyl α-chloroacrylate copolymer, anα-methylstyrene-acrylonitrile-acrylic ester copolymer, a vinyl chlorideresin, a rosin-modified maleic acid resin, a phenol resin, an epoxyresin, a polyethylene resin, a polypropylene resin, an ionomer resin, apolyurethane resin, a silicone resin, a ketone resin, an ethylene-ethylacrylate copolymer, a xylene resin, a polyvinyl butyral resin and thelike. These thermoplastic resins may be used either singly or incombination.

To the toner of the invention or the toner resin used therein, anappropriate amount of a known antioxidant may be added as required. Asthe antioxidant, a hindered phenol-based antioxidant, an aromaticamine-based antioxidant, a hindered amine-based antioxidant, asulfide-based antioxidant, an organophosphorus-based antioxidant and thelike are available. Of these, a hindered phenol-based antioxidant ispreferable. The antioxidants may be used either singly or incombination.

Further, to the toner of the invention or the toner resin used therein,other than the foregoing additives, for example, an age resistor, anantiozonant, an ultraviolet absorber, a light stabilizer, a softeningagent, a reinforcing agent, a filler, a mastication accelerator, afoaming agent, a foaming aid, a lubricant, an inner release agent, aflame retardant, an antistatic agent for kneading, a colorant, acoupling agent, an antiseptic, a flavor and the like may be added asrequired.

The toner for development of an electrostatically charged image in theinvention usually contains 25 to 95% by weight of a toner binder (tonerresin), 0 to 10% by weight of a colorant, 0 to 70% by weight of amagnetic powder, 0 to 10% by weight of a charge control agent and 0 to10% by weight of a lubricant. Further, 0 to 1.5% by weight of afluidizing agent and 0 to 1.5% by weight of a cleaning aid are added asexternal additives.

As the colorant, organic or inorganic colorants such as carbon black,copper oxide, manganese dioxide, aniline black, activated carbon,nonmagnetic ferrite, magnetic ferrite, magnetite, iron black, benzidineyellow, disazo yellow, quinacridone, a naphthol-based azo pigment,quinacridone, Rhodamine B, phthalocyanine, titanium white, zinc oxideand the like are available. By the way, when a magnetic powder in amagnetic toner itself is colored (black), the colorant is notnecessarily used. As the magnetic powder, for example, iron, cobalt,nickel, magnetite, hematite, ferrite and the like are used. The particlediameter of the magnetic powder is selected in the range of, usually0.05 to 1 μm, preferably 0.1 to 0.5 μm.

Further, the charge control agent is a substance capable of providingpositive or negative charge by frictional charging. As this substance,for example, nigrosine base EX (made by Orient Chemical Industries, Co.,Ltd.), P-51 (made by Orient Chemical Industries, Co., Ltd.), Copy ChargePXVP 435 (made by Hoechst Corp.), alkoxylamine, alkylamide, a molybdicacid chelate pigment, PLZ 1001 (made by Shikoku Chemicals Corporation),BONTRON S-22 (made by Orient Chemical Industries, Co., Ltd.), BONTRONS-34 (made by Orient Chemical Industries, Co., Ltd.), BONTRON E-81 (madeby Orient Chemical Industries, Co., Ltd.), BONTRON E-84 (made by OrientChemical Industries, Co., Ltd.), Spilon black TRH (made by HodogayaChemical Co., Ltd.), a thioindigo-based pigment, Copy Charge NXVP 434,BONTRON E-89 (made by Orient Chemical Industries, Co., Ltd.), magnesiumfluoride, fluorocarbon, a hydroxycarboxylic acid metal complex, adicarboxylic acid metal complex, an amino acid metal complex, a diketonemetal complex, a diamine metal complex, a metal complex having an azogroup-containing benzene-benzene derivative skeleton, a metal complexhaving an azo group-containing benzene-naphthalene derivative skeleton,benzyldimethylhexadecylammonium chloride, decyltrimethylammoniumchloride, a metal complex, a nigrosine base, nigrosine hydrochloride,safranine, crystal violet, a quaternary ammonium salt, an alkylsalicylicacid metal complex, a calix allene-based compound, a boron compound, afluorine-containing quaternary ammonium salt, an azo-based metalcomplex, a triphenylmethane dye, dibutyltin oxide and the like areavailable.

As the lubricant, for example, polytetrafluoroethylene, a low-molecularpolyolefin, an aliphatic acid, a metal salt and an amide thereof and thelike can be used.

Meanwhile, as the fluidizing agent used as an external additive, forexample, inorganic fine particles having a particle diameter of severaltens of nanometers, specifically, colloidal silica, alumina, titaniumoxide, zinc oxide, magnesium fluoride, silicon carbide, boron carbide,titanium carbide, zirconium carbide, boron nitride, titanium nitride,zirconium nitride, magnetite, molybdenum disulfide, aluminum stearate,magnesium stearate, zinc stearate and the like can be used. Thesefluidizing agents may be rendered hydrophobic with a silane-based ortitanium-based coupling agent, a higher fatty acid, silicone oil, asurfactant or the like.

Further, preferable examples of the cleaning aid used as an externaladditive include fine particles of polystyrene, polymethyl methacrylate,polyacrylate, polybenzoguanamine, a silicone resin,polytetrafluoroethylene, polyethylene, polypropylene and the like.

A method for producing the toner of the invention is not particularlylimited. A known method such as a mechanical grinding method, aspray-drying method, a chemical polymerization method, a wet granulationmethod or the like can be used. Of these, the mechanical grinding methodis a method in which the toner components are dry-blended, melt-kneaded,then coarsely crushed, finally finely ground with a jet mill or thelike, and further, as required, classified for controlling the particlediameter to obtain fine particles having a volume-average particlediameter of 5 to 20 μm.

The thus-formed toner for development of an electrostatically chargedimage is used as a developer for two-component development by beingmixed with carrier particles, or is singly used as a developer formonocomponent development. As the carrier herein, for example, amagnetic powder carrier, a magnetic powder resin-coated carrier, abinder carrier, a glass bead and the like are available. The particlediameter of these carriers is usually 20 to 500 μm.

As the magnetic powder carrier, for example, metals such as iron,nickel, ferrite, magnetite, cobalt and the like, alloys or mixtures ofthese metals and metals such as zinc, antimony, aluminum, lead, tin,bismuth, beryllium, manganese, selenium, tungsten, zirconium, vanadiumand the like, metal oxides such as iron oxide, titanium oxide, magnesiumoxide and the like, nitrides such as chromium nitride, vanadium nitrideand the like, mixtures with carbides such as silicon carbide, tungstencarbide and the like, and so forth are available.

As the magnetic powder resin-coated carrier, a carrier in which theforegoing magnetic powder particles are used as a core and coated withthe following resins is used. As the coating resin, for example,polyethylene, a silicone resin, a fluororesin, a styrene resin, anacrylic resin, a styrene-acrylic resin, polyvinyl acetate, cellulosederivatives, a maleic acid resin, an epoxy resin, polyvinyl chloride,polyvinylidene chloride, polyvinyl bromide, polyvinylidene bromide, apolycarbonate, a polyester, polypropylene, a phenol resin, polyvinylalcohol, a fumaric ester resin, polyacrylonitrile, polyvinyl ether,chloroprene rubber, an acetal resin, a ketone resin, a xylene resin,butadiene rubber, a styrene-butadiene copolymer, polyurethane and thelike can be used. This magnetic powder resin-coated carrier may contain,as required, conductive fine particles (carbon black, conductive metaloxide and metallic powder), inorganic fillers (silica, silicon nitride,boron nitride, alumina, zirconia, silicon carbide, boron carbide,titanium oxide, clay, talc and glass fibers), the charge control agentsmentioned above and the like. The film thickness of the resin coated onthe carrier core is preferably 0.1 to 5 μm.

The toner for development of an electrostatically charged image in theinvention is used by being transferred and fixed on a support (paper, anOHP film such as a polyester or the like). As the fixing method, forexample, press fixing, heat fixing (SURF fixing, fixing with a hotplate, oven fixing, infrared lamp fixing or the like), contactheat-pressure fixing, flash fixing, solvent fixing and the like can beapplied. Contact heat-pressure fixing with a heating roll is preferable.And, in this case, the lowest fixing temperature of a toner ispreferably 140° C. or less. A toner capable of the low-temperaturefixing at 130° C. or less is especially preferable.

The toner of the invention can be applied as a toner of any type ofmagnetic monocomponent development, magnetic two-component development,nonmagnetic monocomponent development, nonmagnetic two-componentdevelopment and liquid development. It is advantageously used as a tonerfor magnetic monocomponent development, magnetic two-componentdevelopment and nonmagnetic monocomponent development.

The toner of the invention can be applied to various developmentmethods. For example, it can be applied to a magnetic brush developmentmethod, a cascade development method, a method using a conductivemagnetic toner described in the specification of U.S. Pat. No.3,909,258, a method using a highly resistant magnetic toner as describedin Japanese Patent Laid-Open No. 31,136/1978, a method described inJapanese Patent Laid-Open Nos. 42,121/1979, 18,656/1980 and 43,027/1979,a fur brush development method, a powder clouding method, an impressiondevelopment method, a microtoning method, a contact development method,a touchdown development method, a magnedynamic development method, ajumping method, an FEED (Floating Electrode Effect Development) method,an FMT (Fine Micro Toning System) development method, NSP (Non MagneticSingle Component Development Process) and the like can be applied.

The toner of the invention can be applied to any machine of coronacharge (corotron system, scorotron system or the like) and contactcharge (charge roll system, charge brush system or the like). Further, amethod having no cleaning step, a blade method, a fur brush method, amagnetic brush method, a roller cleaning method and the like areavailable. A blade method and a method having no cleaning step arepreferable.

Next, the toner of the invention can be applied to any of an organicelectrophotographic photoreceptor (layered type or single-layer type)and an inorganic photoreceptor (amorphous silicon, amorphous selenium,selenium-based photoreceptor or germanium-based photoreceptor). It isespecially preferable to apply the same to an organicelectrophotographic photoreceptor and an inorganic photoreceptor usingamorphous silicon.

Moreover, the toner of the invention has characteristics that it can beapplied to (1) any of a reversible development process and a normaldevelopment process, (2) any of positively charged and negativelycharged toners, (3) any of monochromic and color printers, (4) any of ananalog printing machine and a digital printing machine, and (5) acopying machine, a printer (a laser beam printer, a liquid crystalprinter or the like), a facsimile and a combined machine of these.

II. Second Invention

The resin composition in the second invention (hereinafter sometimessimply referred to as “the invention” in this column) is a substantiallytransparent resin composition comprising (a) 1 to 99% by weight of apolystyrene-type polymer component and (b) 1 to 99% by weight of apetroleum resin-based polymer component in which when the petroleumresin-based polymer forms a resin composition with the polystyrene-typepolymer at a weight ratio of 1:1, total light transmission measuredaccording to JIS K 7105 on a film-like molded product of the resincomposition having a thickness of 3 mm is 60% or more of a quantity ofincident light. And, with respect to the composition ratio of thepolystyrene-type polymer component as component (a) and the petroleumresin-based polymer as component (b), it is preferable that thepolystyrene-type polymer component (a) is 10 to 65% by weight and thepetroleum resin-based polymer component (b) is 35 to 90% by weight.Further, it is especially preferable that the polystyrene-type polymercomponent (a) is 10 to 49% by weight and the petroleum resin-basedpolymer component (b) is 51 to 90% by weight, because a resincomposition having such an appropriate mechanical strength that it isnot too strong nor brittle and can withstand practical use is obtained.

Next, the polystyrene-type polymer used as component (a) of the resincomposition may be a styrene homopolymer or a styrene-acrylic copolymerin which a weight ratio of a content of an unsaturated carboxylic esterunit to a content of a styrene unit in the copolymer is 1:1 or more. Asthis unsaturated carboxylic ester, unsaturated carboxylic esterscomprising unsaturated carboxylic acids such as acrylic acid,methacrylic acid, maleic acid, fumaric acid, maleic anhydride and thelike and alcohols containing 1 to 18 carbon atoms or hydroxy compounds,or those obtained by copolymerizing acrylonitrile and the like as acomonomer are used. As an alkyl group present in an ester moiety of theunsaturated carboxylic esters, a methyl group, an ethyl group, a propylgroup, a butyl group, a pentyl group, a hexyl group, a heptyl group, anoctyl group, a nonyl group, a decyl group, an undecyl group, a dodecylgroup, a stearyl group and the like are used. In addition, a phenylgroup and a benzyl group are also available. In these unsaturatedcarboxylic esters, especially preferable examples of the comonomer ofthe polystyrene-type copolymer used as component (a) include methylacrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethylmethacrylate, butyl methacrylate, isobutyl methacrylate and 2-ethylhexylmethacrylate.

Further, with respect to the copolymer of styrene and unsaturatedcarboxylic esters, a copolymer in which a weight ratio of a content of astyrene unit (structural unit made of the styrene residue in the polymerchain) to a content of an unsaturated carboxylic ester unit (structuralunit made of the unsaturated carboxylic ester residue in the polymerchain) is higher than 1.1 is preferably used. The reason is that whenthe weight ratio is less than 1.1, the properties of the copolymer arestrongly influenced by the properties of the unsaturated carboxylicester homopolymer to decrease compatibility with the petroleumresin-based polymer as component (b), and further despite the samemolecular weight, the melt index of this copolymer is decreased so thatthe kneading property of both the components is poor and the glasstransition temperature is decreased to invite the decrease inanti-blocking property.

Besides, with respect to the molecular weight of the polystyrene-typepolymer, in either the styrene homopolymer or the copolymer of styreneand the unsaturated carboxylic esters, the weight-average molecularweight measured by gel permeation chromatography and calculated aspolystyrene is 40,000 to 1,000,000, preferably 100,000 to 400,000, andthe number-average molecular weight is 10,000 to 500,000, preferably40,000 to 200,000. When the weight-average molecular weight of thepolystyrene-type polymer as component (a) is less than 40,000 or thenumber-average molecular weight thereof is less than 10,000, there is apossibility that the mechanical strengths of the resin compositioncomprising this and the petroleum resin-based polymer as component (b)are decreased and a large amount of a finely divided component is formedin the toner production to decrease the productivity of the toner or todecrease the storage stability of a printed image when it is used as atoner for development of an electrostatically charged image. Moreover,when the weight-average molecular weight of the polystyrene-type polymerexceeds 1,000,000 or the number-average molecular weight thereof exceeds500,000, the softening temperature of the resin composition comprisingthis and the petroleum resin-based polymer as component (b) becomes toohigh, which makes the low-temperature fixing difficult. Further, themechanical strengths become too high, which sometimes invites thedecrease in grindability of the toner for development of anelectrostatically charged image. As the polystyrene-type polymer, apolymer containing a fluidity improver such as liquid paraffin or thelike may be used.

Next, the petroleum resin-based polymer as component (b) used herein canproperly be selected from those produced by subjecting a C₅ fraction ora C₉ fraction obtained through petroleum refining or naphtha thermalcracking to cationic polymerization, radical polymerization, heatpolymerization, anionic polymerization, coordinated ionicpolymerization, suspension polymerization, emulsion polymerization,polymerization with a transition metal complex catalyst or the like.These petroleum resins include an aliphatic petroleum resin obtained byusing a C₄-C₅ fraction as a starting material, a dicyclopentadiene-basedpetroleum resin obtained by using a fraction composed mainly ofdicyclopentadiene as a starting material, an aromatic petroleum resinobtained by using a C₈-C₁₀ fraction having a high content of an aromatichydrocarbon such as styrene, vinyltoluene, methylstyrene,isopropenyltoluene, indene, alkyl-substituted indene or the like as astarting material and a copolymer thereof according to the type of thepolymerizable monomer used as the starting material.

And, in the production of these petroleum resins, as the polymerizablemonomer being the starting material, fractions obtained from a petroleumrefining step are, in many cases, used in the polymerization as such, orthe fractions subjected to simple purification are singly used in thepolymerization or plural such fractions are mixed and used in thepolymerization. After each monomer is separated and purified, it issingly used in the polymerization, or plural such monomers are mixed andused in the polymerization. In this case, a petroleum resin obtained byseparating and purifying each monomer and polymerizing the same providesuniform physicochemical properties. Thus, it is preferably applied tousage requiring high-level control of properties, for example, to atoner resin.

Further, preferable examples of a polymerization method in producing apetroleum resin by polymerizing these monomers include aFriedel-Crafts-type cationic polymerization method using a Lewis acidand a heat polymerization method. In case of the Friedel-Crafts-typecationic polymerization method, aluminum chloride, aluminum bromide,dichloroethylaluminum, titanium tetrachloride, tin tetrachloride, borontrifluoride and the like are used as a catalyst, and aromatichydrocarbons such as toluene, xylene, ethylbenzene, mesitylene cumene,cymene and the like, aliphatic hydrocarbons such as pentane, hexane,heptane, octane, cyclohexane, cyclopentane, methylcyclohexane and thelike, and mixtures thereof are used as a polymerization solvent. And,the ratio of the catalyst used is 0.01 to 5 parts by weight, preferably0.05 to 3 parts by weight per part by weight of the monomer. Apolymerization temperature varies with the type of the monomer or thetype of the catalyst. The polymerization is conducted at −20 to 60° C.An appropriate polymerization time is 0.5 to 5 hours. Further, after thepolymerization, the catalyst is decomposed with an alkaline aqueoussolution, methanol or the like, and washed with water, and a lowpolymer, an unreacted monomer and a solvent are removed under reducedpressure to obtain a purified petroleum resin.

Since the thus-obtained petroleum resin contains unsaturated bonds oraromatic rings in various forms in the polymer chain, a petroleum resinof which the properties are improved by hydrogenating these unsaturatedbond sites can be obtained. The hydrogenation reaction of the petroleumresin can be conducted by a known method. For example, it is advisablethat a petroleum resin having an unsaturated bond is dissolved in asolvent such as hexane, heptane, octane, cyclohexane, methylcyclohexane,decalin, benzene, toluene, xylene or the like, a catalyst such asnickel, palladium, ruthenium, rhodium, cobalt, platinum, tungsten,chromium, molybdenum, rhenium, manganese or the like is added theretoand the reaction is conducted at 0 to 350° C., preferably 150 to 260° C.and a hydrogen pressure of normal pressure to 200 kg/cm², preferably 30to 100 kg/cm². In this case, a catalyst supported on a carrier such asalumina, silica, zeolite, diatomaceous earth or the like may be used.

When the thus-obtained petroleum resin is used as a petroleumresin-based polymer being component (b) of the resin composition in theinvention, the weight-average molecular weight is preferably 400 to5,000. When the weight-average molecular weight of the petroleum resinused as component (b) is less than 400, the mechanical strength of theresin composition comprising this and component (a) is likely to beunsatisfactory. Further, when the weight-average molecular weightexceeds 5,000, the low-temperature fixability of the toner obtained byusing the resin composition comprising this and component (a) is likelyto be unsatisfactory.

Regarding the petroleum resin used as component (b) of the resincomposition of the invention, the softening temperature thereof is lowerthan 130° C., more preferably lower than 120° C. This is because whenthe softening temperature of the petroleum resin as component (b) ishigher than 130° C., the low-temperature fixability of the toner fordevelopment of an electrostatically charged image produced by using theresin composition comprising this and component (a) is sometimesunsatisfactory. Further, with respect to the softening temperature ofthe petroleum resin, a ½ outflow temperature measured using a flowtester is 80 to 130° C., preferably 90 to 130° C. When this temperatureis less than 80° C., a toner for development of an electrostaticallycharged image produced by using the resin composition containing this ascomponent (b) tends to cause toner blocking during storage thereof.Further, when this temperature exceeds 140° C., the low-temperaturefixability of the toner using the same is sometimes not obtainedsatisfactorily.

Further, the bromine value of the petroleum resin used as component (b)is not particularly limited unless the total light transmission of theresin composition obtained by mixing this with component (a) is lessthan 60% of the quantity of incident light. It is 60 g/100 g or less,preferably 10 g/100 g or less. This is because when the bromine valueexceeds 60 g/100 g, the coloration occurs drastically and the totallight transmission of the resin composition obtained by mixing this withcomponent (a) is liable to be less than 60% of the quantity of incidentlight.

And, the content of the aromatic hydrocarbon unit contained in thepolymer chain of the petroleum resin used as this component (b) is notparticularly limited unless the total light transmission of the resincomposition comprising this and component (a) at the weight ratio of 1:1is 60% or more, preferably 80% or more and the haze is 40% or less,preferably 15% or less. An aromatic petroleum resin, a hydrogenatedaromatic petroleum resin, an aromatic-aliphatic petroleum resin, ahydrogenated aromatic-aliphatic petroleum resin, anaromatic-dicyclopentadiene polymer-based petroleum resin and ahydrogenated aromatic-dicyclopentadiene polymer-based petroleum resin inan amount of 30% by weight or more, preferably 40% by weight or more canbe used. Of these various petroleum resins, especially an aromaticpetroleum resin or an aromatic copolymer-based petroleum resin having ahigh content of an aromatic hydrocarbon group is preferably used becauseit is excellent in compatibility with the polystyrene-type polymer ascomponent (a).

And, among aromatic petroleum resins appropriate as the petroleumresin-based polymer used as component (b), an aromatic petroleum resinproduced from one or more monomers selected from vinyltoluene,α-methylstyrene, isopropenyltoluene and indene as a starting material bya Friedel-Crafts-type cationic polymerization method or aheat-polymerization method using a Friedel-Crafts catalyst, a Lewis acidor the like is appropriately used because of excellent hue.

Moreover, as this petroleum resin-based polymer component (b), acompound in which at least a part of the unsaturated bond and/or thearomatic ring is hydrogenated is also preferably used.

Further, as the petroleum resin-based polymer as component (b), an estergroup-containing dicyclopentadiene polymer-based petroleum resin havingthe saponification value of 10 to 400 mg KOH/g can be used. When thecontent of the aromatic hydrocarbon unit contained in the polymer chainof the petroleum resin is low, it has low compatibility with thepolystyrene-type polymer. However, by introducing a functional groupinto the petroleum resin, the compatibility with the polystyrene-typepolymer can be improved. Especially, an ester group-containingdicyclopentadiene polymer-based petroleum resin obtained by introducinga maleic ester, an acrylic ester, a methacrylic ester or the like intoan unsaturated bond site of a polymer chain of a dicyclopentadienepolymer-based petroleum resin through a polymerization reaction isexcellent in compatibility with the polystyrene-type polymer ascomponent (a). The ratio of the ester group introduced herein is 10 to400 mg KOH/g, preferably 50 to 300 mg KOH/g in terms of a saponificationvalue. When this saponification value is less than 10 mg KOH/g, thecompatibility with the polystyrene-type polymer as component (a) isinsufficient. Further, when this saponification value exceeds 400 mgKOH/g, charging characteristics of the toner using the resin compositioncomprising this and component (a) is liable to be decreased. Moreover, ahydroxyl group-containing dicyclopentadiene polymer-based petroleumresin having a hydroxyl value of 10 to 400 mg KOH/g, preferably 50 to300 mg KOH/g, more preferably 100 to 250 mg KOH/g can be used. When thishydroxyl value is less than 10 mg KOH/g, the compatibility withcomponent (a) is insufficient. When it exceeds 400, chargingcharacteristics are liable to be decreased.

In addition, as the petroleum resin-based polymer as component (b), itis advisable to use a polymer in which weight loss at 150° C. of avolatile component contained therein as measured in air at roomtemperature to 600° C. with a rate of rise of 10° C./min by thermalgravimetry (TG-DTA) is 1% by weight or less, preferably 0.7% by weightor less. Such a petroleum resin-based polymer having the weight loss at150° C. of 1% by weight or less can be obtained by a method in which aningredient incapable of polymerization is removed from a startingmaterial before the polymerization or a method in which after thepolymerization of a petroleum resin starting material, the heating isconducted under reduced pressure to remove a low polymer or an unreactedproduct. When a toner for development of an electrostatically chargedimage produced using as a binder resin a resin composition containing apetroleum resin-based polymer in which weight loss at 150° C. exceeds 1%by weight is used herein, an odor is sometimes given off in fixing thetoner for development of an electrostatically charged image atapproximately 150° C.

With respect to the hue of the petroleum resin as component (b), theGardener color number measured in a molten condition according to JIS K5400 is 3 or less, preferably 2 or less. Further, with respect to thehue of the petroleum resin, when the Hazen color number measuredaccording to JIS K 6901 is 250 or less, the total light transmission ofthe resin composition obtained by using the same is increased, and atoner binder resin excellent in transparency can be obtained. Thepetroleum resin having the Gardener color number of 3 or less or theHazen color number of 250 or less can be obtained by a method in whichthe resin starting material is purified well and polymerized, a methodin which the polymerization is conducted at a low temperature or amethod in which an aliphatic unsaturated bond of a colored petroleumresin formed by polymerization is hydrogenated.

Next, when the polystyrene-type polymer as component (a) and thepetroleum resin as component (b) are kneaded to produce the resincomposition, it can be conducted using a melt kneader ordinarilyemployed in molding a thermoplastic resin. The resin compositionobtained herein is formed by melt-kneading both the components (a) and(b) at the composition ratio of 1 to 99% by weight. More preferably, thecomposition ratio is that the polystyrene-type polymer as component (a)is 10 to 65% by weight and the petroleum resin as component (b) is 35 to90% by weight. Further preferably, the composition ratio is that thepolystyrene-type polymer as component (a) is 10 to 49% by weight and thepetroleum resin as component (b) is 51 to 90% by weight.

When the weight ratio of component (a) to component (b) is 1:1 in thethus-obtained resin composition, it is a substantially transparent resincomposition in which the total light transmission measured according toJIS K 7105 on a film-like molded product having a thickness of 3 mm is60% or more of the quantity of incident light. Further, a resincomposition excellent in transparency can be obtained in which haze thatis a ratio, expressed by percentage, of scattered light transmission tototal light transmission as measured on a film-like molded product ofthis resin composition having a thickness of 3 mm is 40% or less.

Further, the glass transition temperature of this resin composition ispreferably 50° C. or more, more preferably 60° C. or more. When theglass transition temperature of this resin composition is less than 50°C., a toner produced by using this tends to cause toner blocking bywhich agglomeration occurs during storage thereof.

And, the outflow starting temperature of the resin composition measuredby the flow tester is 80 to 140° C., preferably 100 to 130° C. When thisoutflow starting temperature is less than 80° C., the toner particlestend to be agglomerated within the unit before development by frictionalheat or the like. Further, when the outflow starting temperature exceeds140° C., the low-temperature fixability is sometimes insufficient.

Further, in the toner of the invention, wax can be used as a toner resinalong with the toner binder resin. The combined use of this wax canimprove releasability of the toner. The wax is not particularly limited,and any of known waxes can selectively be used. Specifically, thosedescribed in the first invention are applied. Of these, polyethylenewax, polypropylene wax, oxidized polyethylene wax and oxidizedpolypropylene wax are preferable. These waxes may be used either singlyor in combination.

Moreover, when the binder resin of the invention and the wax are used incombination, the content of the wax based on the total toner resin ispreferably 30% by weight or less. When the content exceeds 30% byweight, there is a possibility that the decrease in glass transitiontemperature is invited to decrease the anti-blocking property.

Further, a known thermoplastic resin can jointly be used, as required,in the toner of the invention. As the thermoplastic resin, specifically,those described in the first invention are applied. These thermoplasticresins can be used either singly or in combination.

To the toner of the invention or the toner resin used therein, anappropriate amount of a known antioxidant may be added as required. Asthe antioxidant, a hindered phenol-based antioxidant, an aromaticamine-based antioxidant, a hindered amine-based antioxidant, asulfide-based antioxidant, an organophosphorus-based antioxidant and thelike are available. Of these, a hindered phenol-based antioxidant ispreferable. The antioxidants may be used either singly or incombination.

Further, to the toner of the invention or the toner resin used therein,other than the foregoing additives, for example, an age resistor, anantiozonant, an ultraviolet absorber, a light stabilizer, a softeningagent, a reinforcing agent, a filler, a mastication accelerator, afoaming agent, a foaming aid, a lubricant, an inner release agent, aflame retardant, an antistatic agent for kneading, a colorant, acoupling agent, an antiseptic, a flavor and the like may be added asrequired.

The toner for development of an electrostatically charged image in theinvention usually contains 25 to 95% by weight of a toner binder (tonerresin), 0 to 10% by weight of a colorant, 0 to 70% by weight of amagnetic powder, 0 to 10 by weight of a charge control agent and 0 to10% by weight of a lubricant. Further, 0 to 1.5% by weight of afluidizing agent and 0 to 1.5% of a cleaning aid are added as externaladditives.

As the colorant, specifically, those described in the first inventionare applied. As the magnetic powder, for example, iron, cobalt, nickel,magnetite, hematite, ferrite and the like are used. The particlediameter of the magnetic powder is selected in the range of, usually0.05 to 1 μm, preferably 0.1 to 0.5 μm.

Further, the charge control agent is a substance capable of providingpositive or negative charge by frictional charging. Specifically, thosedescribed in the first invention are applied.

As the lubricant, for example, polytetrafluoroethylene, a low-molecularpolyolefin, an aliphatic acid, a metal salt and an amide thereof, andthe like can be used.

Meanwhile, as the cleaning aid used as an external additive,specifically, those described in the first invention are applied.

Further, preferable examples of the cleaning aid used as an externaladditive include fine particles of polystyrene, polymethyl methacrylate,polyacrylate, polybenzoguanamine, a silicone resin,polytetrafluoroethylene, polyethylene, polypropylene and the like.

A method for preparing the toner of the invention is not particularlylimited. A known method such as a mechanical grinding method, aspray-drying method, a chemical polymerization method, a wet granulationmethod or the like can be used. Of these, the mechanical grinding methodis a method in which the toner components are dry-blended, melt-kneaded,then coarsely crushed, finally finely ground with a jet mill or thelike, and further, as required, classified for controlling the particlediameter to obtain fine particles having a volume-average particlediameter of 5 to 15 μm.

The thus-formed toner for development of an electrostatically chargedimage is used as a developer for two-component development by beingmixed with carrier particles, or is singly used as a developer formonocomponent development. As the carrier herein, for example, amagnetic powder carrier, a magnetic powder resin-coated carrier, abinder carrier, a glass bead and the like are applied. The particlediameter of these carriers is usually 20 to 500 μm.

As the magnetic powder carrier, specifically, those described in thefirst invention are applied.

As the magnetic powder resin-coated carrier, a carrier in which theforegoing magnetic powder particles are used as a core and coated withthe following resins is used. As the coating resin, specifically, thosedescribed in the first invention are applied. This magnetic powderresin-coated carrier may contain, as required, conductive fine particles(carbon black, conductive metal oxide and metallic powder), inorganicfillers (silica, silicon nitride, boron nitride, alumina, zirconia,silicon carbide, boron carbide, titanium oxide, clay, talc and glassfibers), the charge control agents mentioned above and the like. Thefilm thickness of the resin coated on the carrier core is preferably 0.1to 5 μm.

The toner for development of an electrostatically charged image in theinvention is used by being transferred and fixed on a support (paper, anOHP film such as a polyester or the like). As the fixing method, forexample, press fixing, heat fixing (SURF fixing, fixing with a hotplate, oven fixing, infrared lamp fixing or the like), contactheat-pressure fixing, flash fixing, solvent fixing and the like can beapplied. Contact heat-pressure fixing with a heating roll is preferable.And, in this case, the lowest fixing temperature of the toner ispreferably 145° C. or less. A toner capable of the low-temperaturefixing at 140° C. or less is especially preferable.

The toner of the invention can be applied as a toner of any type ofmagnetic monocomponent development, magnetic two-component development,nonmagnetic monocomponent development, nonmagnetic two-componentdevelopment and liquid development. It is advantageously used formagnetic monocomponent development, magnetic two-component developmentand nonmagnetic monocomponent development.

The toner of the invention can be applied to various developmentmethods. Specifically, it is applied to those described in the firstinvention.

The toner of the invention can be applied to any machine of coronacharge (corotron system, scorotron system or the like) and contactcharge (charge roll system, charge brush system or the like). Further, amethod having no cleaning step, a blade method, a fur brush method, amagnetic brush method, a roller cleaning method and the like can beapplied. A blade method and a method having no cleaning step arepreferable.

Next, the toner of the invention can be applied to any of an organicelectrophotographic photoreceptor (layered type or single-layer type)and an inorganic photoreceptor (amorphous silicon, amorphous selenium,selenium-based photoreceptor or germanium-based photoreceptor). It isespecially preferable to apply the same to an organicelectrophotographic photoreceptor and an inorganic photoreceptor usingamorphous silicon.

Moreover, the toner of the invention has characteristics that it can beapplied to (1) any of a reversible development process and a normaldevelopment process, (2) any of positively charged and negativelycharged toners, (3) any of monochromic and color printing machines, (4)any of an analog printing machine and a digital printing machine, and(5) a copying machine, a printer (laser beam printer, a liquid crystalprinter and the like), a facsimile and a combined machine of these.

III. Third Invention

The third invention (hereinafter sometimes simply referred to as “theinvention” in this column) is [I] a toner binder resin for developmentof an electrostatically charged image, containing at least one resinselected from (a) a terpene resin, (b) a rosin resin and (c) ahydrogenated aromatic petroleum resin, and further [2] a toner binderresin for development of an electrostatically charged image, containing(A) at least one resin selected from (a) a terpene resin, (b) a rosinresin and (c) a hydrogenated aromatic petroleum resin, and (B) a styreneresin and/or a polyester resin.

As the terpene resin (a) herein, polymers obtained by using terpenecompounds such as α-pinene, β-pinene, limonene, dipentene, camphene,Δ³-carene and the like as a starting material, copolymers of the samewith other monomers and modified products of these polymers are applied.Of these, a component derived from at least one of α-pinene, β-pineneand dipentene, namely, a polymer or a copolymer obtained by using atleast one of α-pinene, β-pinene and dipentene as a starting material, acopolymer of at least one of these and another monomer, and a modifiedproduct of the polymer or the copolymer are preferably used. As thecopolymer, aromatic-terpene copolymers (copolymers of styrenes such asstyrene, vinyltoluene, α-methylstyrene, β-methylstyrene,isopropenyltoluene and the like or indenes such as indene, methylindeneand the like and terpenes), and terpene phenol resins (copolymer resinsof phenols such as phenol, alkylphenol and the like and bisphenols suchas bisphenol A, bisphenol F, bisphenol Z and the like and terpenes) arepreferably used. Further, as the modified products of these resins,resins obtained by hydrogenating a part or the whole of an aliphaticunsaturated bond and/or an aromatic unsaturated bond are available. Thecontent of the component derived from at least one of α-pinene, β-pineneand dipentene is preferably 30% by weight or more based on the terpeneresin because appropriate mechanical strengths are provided.

(b) As the rosin resin, gum rosin, wood rosin, tall oil rosin and thoseobtained by processing and modifying them can be used. As the modifiedrosin, metal salts with zinc, calcium, magnesium and the like, esterrubbers (rosin esterified with alcohols such as glycerin,pentaerythritol, benzyl alcohol and the like), a rosin-maleic acidresin, a rosin-modified phenol resin, a rosin-modified alkyd resin, ahydrogenated rosin resin and the like are available. Of these, esterrubbers and a rosin-maleic acid resin are preferable.

Further, as the hydrogenated aromatic petroleum resin (c), a resinformed by using at least one aromatic vinyl compound selected from a C₉fraction resulting from thermal cracking of petroleum naphtha, styrene,α-methylstyrene, β-methylstyrene, vinyltoluene, isopropenyltoluene,indene, alkyl-substituted indene, allylbenzene, allyltoluene,tert-butylstyrene and tert-butylallylbenzene as a starting material,subjecting the same to cationic polymerization, radical polymerization,heat polymerization, anionic polymerization, coordinated ionicpolymerization, suspension polymerization, emulsion polymerization orpolymerization with a transition metal complex catalyst, and thenhydrogenating a part or the whole of an aromatic ring using a knownaromatic ring hydrogenation catalyst such as nickel or the like is used.In the production of these petroleum resins, as the polymerizablemonomer being the starting material, fractions obtained from a petroleumrefining step are, in many cases, used in the polymerization as such, orthe fractions are subjected to simple purification, and they are usedsingly in the polymerization or plural such fractions are mixed and usedin the polymerization. After each monomer is separated and purified, itis singly used in the polymerization, or plural such monomers are mixedand used in the polymerization. In this case, a petroleum resin obtainedby separating and purifying each monomer and polymerizing the sameprovides uniform physicochemical properties. Thus, it is preferablyapplied to usage requiring high-level control of properties, forexample, to a toner resin. The hydrogenation rate of aromatics, (contentof aromatics before hydrogenation−content of aromatics afterhydrogenation)/(content of aromatics before hydrogenation)×100 (%)(content of aromatics was obtained from an absorption peak intensity atwavenumber of 700 cm⁻¹ in the infrared absorption analysis), is optionalunless the effects of the invention are impaired. It is preferably 10 to90%, more preferably 30 to 70%. When the hydrogenation rate is less than10%, there is a likelihood that the resin is colored and an odor isgiven off in fixation after formation of a toner. When the hydrogenationrate exceeds 90%, there is a likelihood that the compatibility withpolystyrene, a styrene-unsaturated carbonyl compound copolymer resin, apolyester or the like is decreased and a composition well kneaded is notobtained as will be described later. In case of the Friedel-Crafts-typecationic polymerization method, aluminum chloride, aluminum bromide,dichloroethylaluminum, titanium tetrachloride, tin tetrachloride, borontrifluoride and the like are used as a catalyst, and aromatichydrocarbons such as toluene, xylene, ethylbenzene, mesitylene, cumene,cymene and the like, aliphatic hydrocarbons such as pentane, hexane,heptane, octane, cyclohexane, cyclopentane, methylcyclohexane and thelike, and mixtures thereof are used as a polymerization solvent. And,the ratio of the catalyst used is 0.01 to 5 parts by weight, preferably0.05 to 3 parts by weight per part by weight of the monomer. Thepolymerization temperature varies with the type of the monomer or thetype of the catalyst. The polymerization is conducted at −20 to 60° C.An appropriate polymerization time is 0.5 to 5 hours. Further, after thepolymerization, the catalyst is decomposed with an alkaline aqueoussolution, methanol or the like, and washed with water, and a lowpolymer, an unreacted monomer and a solvent are removed under reducedpressure to obtain a purified petroleum resin. The hydrogenationreaction of the petroleum resin can be conducted by a known method. Forexample, it is advisable that a petroleum resin having an unsaturatedbond is dissolved in a solvent such as hexane, heptane, octane,cyclohexane, methylcyclohexane, decalin, benzene, toluene, xylene or thelike, a catalyst such as nickel, palladium, ruthenium, rhodium, cobalt,platinum, tungsten, chromium, molybdenum, rhenium, manganese or the likeis added thereto, and the reaction is conducted at 0 to 350° C.,preferably 150 to 260° C. and hydrogen pressure of normal pressure to200 kg/cm², preferably 30 to 100 kg/cm². In this case, the catalyst maybe supported on a carrier such as alumina, silica, zeolite, diatomaceousearth or the like. It is advisable that the thus-obtained petroleumresin has the weight-average molecular weight of 400 to 5,000. When theweight-average molecular weight is less than 400, the mechanicalstrength is liable to be unsatisfactory. Further, when it exceeds 5,000,the low-temperature fixability of the resulting toner is liable to beunsatisfactory.

It is preferable that the softening temperature of the terpene resin,the rosin resin and the hydrogenated aromatic petroleum resin is 130° C.or less for attaining the low-temperature fixability. More preferably,it is 120° C. or less.

Further, the total amount of at least one resin selected from (a) aterpene resin, (b) a rosin resin and (c) a hydrogenated aromaticpetroleum resin in the toner binder resin for development of anelectrostatically charged image is 5 to 100% by weight, preferably 15 to90% by weight, more preferably 30 to 80% by weight, further preferably51 to 70% by weight in the toner binder resin for development of anelectrostatically charged image in consideration of a balance of thelow-temperature fixability and the mechanical strength. When it is lessthan 5% by weight, the low-temperature fixability is liable to bedecreased.

Moreover, in the invention, it is advisable to use the styrene resinand/or the polyester resin (B) as the binder resin component.

As the styrene resin, polystyrene and/or a styrene-unsaturated carbonylcompound copolymer resin is preferable. As the unsaturated carbonylcompound, an acrylic ester, a methacrylic ester, acrylonitrile, a maleicester, a fumaric ester, maleic anhydride and the like are used. In theester moiety, alkyl groups, aryl groups and alkenyl groups such asmethyl, ethyl, propyl, isopropyl, butyl, 2-butyl, pentyl, hexyl, heptyl,octyl, nonyl, decyl, undecyl, dodecyl, stearyl, 2-ethylhexyl, benzyl,phenyl, vinyl and allyl are selected. In case of a copolymer of styreneand an acrylic ester compound, the copolymer composition ratio: (styrenecomponent/acrylic component) is preferably more than 1.1. When it isless than 1.1, the properties of the acrylic resin become too strong,involving problems that the kneading property is decreased due to thedecrease in compatibility with the petroleum resin and the decrease inMI, the anti-blocking property is decreased due to the decrease in Tgand the like.

The weight-average molecular weight of polystyrene and thestyrene-unsaturated carbonyl compound copolymer resin is 40,000 to1,000,000, preferably 10,000 to 400,000, and the number-averagemolecular weight thereof is 10,000 to 500,000, preferably 40,000 to200,000. When the weight-average molecular weight is less than 40,000 orthe number-average molecular weight is less than 10,000, the mechanicalstrength of the composition with the terpene resin and/or the rosinresin and/or the hydrogenated aromatic petroleum resin isunsatisfactory, and there is a problem with the storage stability of aprinted image or the like. When the weight-average molecular weight ismore than 1,000,000 or the number-average molecular weight is more than500,000, the softening temperature and the mechanical strength of thecomposition with the terpene resin and/or the rosin resin and/or thehydrogenated aromatic petroleum resin are too high, and there areproblems with the low-temperature fixability and the toner grindability.Further, this polystyrene-type polymer may contain a fluidity improversuch as liquid paraffin or the like.

Further, it is possible to use, as the polyester resin, those obtainedby using the starting materials, α,ω-alkylene diols (C₂-C₁₂) such asethylene glycol, diethylene glycol, triethylene glycol, propyleneglycol, 1,4-dihydroxycyclohexane, bisphenol A, bisphenol A-ethyleneglycol modified diol, 1,3-propylene glycol and the like, dihydricalcohols such as hydrogenated bisphenol A, bisphenol F, bisphenolF-ethylene glycol modified diol, bisphenol S, bisphenol S-ethyleneglycol modified diol, biphenol, biphenol-ethylene glycol modified diol,neopenty glycol and the like and trihydric or higher hydric alcoholssuch as glycerin and the like as an alcohol component, andα,ω-alkylenedicarboxylic acid (C₂-C₁₂), aliphatic dicarboxylic acidssuch as maleic acid, fumaric acid and the like, alicyclic dicarboxylicacids such as 1,4-cyclohexanedicarboxylic acid,2,3-bicyclo[2,2,1]dicarboxylic acid and the like, aromatic dicarboxylicacids such as phthalic acid, isophthalic acid, terephthalic acid,naphthalenedicarboxylic acid, biphenylcarboxylic acid,4,4′-bis(2,2-isopropylidene)dicarboxylic acid and the like, tribasic orhigher basic carboxylic acids such as trimellitic acid and the like,acid halides and ester derivatives thereof and the like as a carboxylicacid component. These starting materials may be used either singly or incombination.

In the toner binder resin for development of an electrostaticallycharged image according to the invention, regarding the mixing ratio of(A) at least one resin selected from (a) the terpene resin, (b) therosin resin and (c) the hydrogenated aromatic petroleum resin and (B)the styrene resin and/or the polyester resin, the weight ratio ofcomponent (A) and component (B)((A)/(B)) is 90/10 to 15/85, preferably80/20 to 30/70, more preferably 70/30 to 51/49. The content (weightratio) [A/(A+B)] of component (A) is appropriately 0.15 to 0.9,preferably 0.3 to 0.8, more preferably 0.51 to 0.7. In this case, theresins of component (A) and the resins of component (B) may be usedeither singly or in combination. In the mixing ratio of both thecomponents, when the content of component (A) is less than 0.15, thereis a possibility that the effect of the invention that thelow-temperature fixability is excellent is not obtained. Further, whenthe content of component (A) exceeds 0.90, there is a possibility thatthe resin composition becomes brittle and is inappropriate for use as atoner binder resin. Further, when this resin composition is used as atoner binder in the range of 0.3 to 0.8 which is preferable as thecontent of component (A), the balance of the properties such as thelow-temperature fixability, the grindability and the like is especiallygood. In the range of 0.51 to 0.7, the more preferable properties areprovided.

Further, the glass transition temperature of this resin composition ispreferably 50° C. or more, further preferably 60° C. or more. When theglass transition temperature of this resin composition is less than 50°C., the toner produced by using the same tends to cause toner blockingby which the toner is agglomerated during storage thereof. With respectto the heat-softening temperature, a composition having a heat-softeningtemperature of 80 to 140° C., preferably 100 to 130° C. is favorablyused. When the heat-softening temperature is less than 80° C., the tonerparticles tend to be agglomerated in an equipment before development bya frictional heat or the like. Moreover, when the heat-softeningtemperature exceeds 140° C., the low-temperature fixability is sometimesinsufficient.

In addition, the mechanical strengths of this resin composition are alsoimportant properties in practical use along with the thermal properties.Accordingly, with respect to the resins used as components (A) and (B)being structural components of the resin composition, resins which haveappropriate mechanical strengths, especially controlled brittleness byadjusting the molecular weight, the copolymerization composition thereofor the like are preferably used.

The thus-obtained toner binder resin of the invention is especiallyappropriate as a binder resin of a toner for contact heat pressurefixation with a heating roll.

The toner for development of an electrostatically charged image in theinvention contains one or more of the toner binder resins as a tonerresin. And, the content of the toner binder resin in this toner resin isnot particularly limited. It is usually 50% by weight or more,preferably 70% by weight or more. When the content of the toner binderis less than 50% by weight, there is a likelihood that the effects ofthe invention are not obtained satisfactorily. When the content is 50%by weight or more, the effects are satisfactorily exhibited. Especiallywhen it is 70% by weight or more, the grindability in the production ofthe toner is good, and a toner good in low-temperature fixability alsois provided.

In the toner of the invention, an elastomer can be used as a toner resinalong with the toner binder resin unless the effects of the inventionare impaired. The combined use of this elastomer improves Theologicalcharacteristics in melting, and an offset generating temperature isincreased. This elastomer is not particularly limited, and any of knowncompounds can selectively be used.

With respect to this elastomer, specifically, those described in thefirst invention are applied. Of these elastomers, a styrene-butadienecopolymer is especially preferable. And, these elastomers may be usedeither singly or in combination.

Further, when the toner binder resin and these elastomers are used incombination, the content of the elastomer based on the total toner resinis preferably 30% by weight or less. When the content exceeds 30% byweight, the grindability in the production of the toner is liable to bedecreased.

Moreover, in the toner of the invention, wax can be used as a tonerresin along with the toner binder resin. The combined use of the wax canimprove releasability of the toner. This wax is not particularlylimited, and any of known waxes can selectively be used.

With respect to this wax, specifically, those described in the firstinvention are applied. Further, as a resin having the same properties aswax, a styrene oligomer, an amorphous poly-α-olefin and the like arepreferably used. Of these, polyethylene wax, polypropylene wax,acid-modified polyethylene wax and acid-modified polypropylene wax areespecially preferable. These waxes may be used either singly or incombination.

Moreover, when the binder resin of the invention and the wax are used incombination, the content of the wax based on the total toner resin ispreferably 30% by weight or less. When the content exceeds 30% byweight, there is a possibility that the decrease in the glass transitiontemperature is invited to decrease the anti-blocking property.

In addition, in the toner of the invention, a known thermoplastic resincan jointly be used as required. With respect to this thermoplasticresin, specifically, those described in the invention are applied. Thesethermoplastic resins may be used either singly or in combination.

To the toner of the invention or the toner resin used therein, anappropriate amount of a known antioxidant may be added as required. Asthe antioxidant, a hindered phenol-based antioxidant, an aromaticamine-based antioxidant, a hindered amine-based antioxidant, asulfide-based antioxidant, an organophosphorus-based antioxidant and thelike are available. Of these, a hindered phenol-based antioxidant ispreferable. The antioxidants may be used either singly or incombination.

Further, to the toner of the invention or the toner resin used therein,other than the foregoing additives, for example, an age resistor, anantiozonant, an ultraviolet absorber, a light stabilizer, a softeningagent, a reinforcing agent, a filler, a mastication accelerator, afoaming agent, a foaming aid, a lubricant, an inner release agent, aflame retardant, an antistatic agent for kneading, a colorant, acoupling agent, an antiseptic, a flavor and the like may be added asrequired.

The toner for development of an electrostatically charged image in theinvention usually contains 25 to 95% by weight of a toner binder (tonerresin), 0 to 10% by weight of a colorant, 0 to 70% by weight of amagnetic powder, 0 to 10 by weight of a charge control agent and 0 to10% by weight of a lubricant. Further, 0 to 1.5% by weight of afluidizing agent and 0 to 1.5% of a cleaning aid are added as externaladditives.

As the colorant, specifically, those described in the first inventionare applied. Further, as the magnetic powder, for example, iron, cobalt,nickel, magnetite, hematite, ferrite and the like are used. The particlediameter of the magnetic powder is selected in the range of, usually0.05 to 1 μm, preferably 0.1 to 0.5 μm.

Further, the charge control agent is a substance capable of providingpositive or negative charge by frictional charging. Specifically, thosedescribed in the first invention are applied.

As the lubricant, for example, polytetrafluoroethylene, a low-molecularpolyolefin, an aliphatic acid, a metal salt and an amide thereof and thelike can be used.

Meanwhile, with respect to the fluidizing agent and the cleaning aidused as external additives, specifically, those described in the firstinvention are also applied.

A method for producing the toner of the invention is not particularlylimited. Specifically, those described in the first invention areapplied.

The thus-formed toner for development of an electrostatically chargedimage is used as a developer for two-component development by beingmixed with carrier particles, or is singly used as a developer formonocomponent development. As the carrier herein, for example, amagnetic powder carrier, a magnetic powder resin-coated carrier, abinder carrier, a glass bead and the like are applied. The particlediameter of these carriers is usually 20 to 500 μm.

As the magnetic powder carrier, specifically, those described in thefirst invention are applied. As the magnetic powder resin-coatedcarrier, a carrier in which the foregoing magnetic powder particles areused as a core and coated with the resin is used. As the coating resin,specifically, those described in the first invention are applied. Thismagnetic powder resin-coated carrier may contain, as required,conductive fine particles (carbon black, conductive metal oxide andmetallic powder), inorganic fillers (silica, silicon nitride, boronnitride, alumina, zirconia, silicon carbide, boron carbide, titaniumoxide, clay, talc and glass fibers), the charge control agents mentionedabove and the like. The film thickness of the resin coated on thecarrier core is preferably 0.1 to 5 μm.

The toner for development of an electrostatically charged image in theinvention is used by being transferred and fixed on a support (paper, anOHP film such as a polyester or the like). As the fixing method, forexample, press fixing, heat fixing (SURF fixing, fixing with a hotplate, oven fixing, infrared lamp fixing or the like), contactheat-pressure fixing, flash fixing, solvent fixing and the like can beapplied. Contact heat-pressure fixing with a heating roll is preferable.And, in this case, the lowest fixing temperature of the toner ispreferably 140° C. or less. A toner capable of the low-temperaturefixing at 130° C. or less is especially preferable.

The toner of the invention can be applied as a toner of any type ofmagnetic monocomponent development, magnetic two-component development,nonmagnetic monocomponent development, nonmagnetic two-componentdevelopment and liquid development. It is advantageously used as a tonerfor magnetic monocomponent development, magnetic two-componentdevelopment and nonmagnetic monocomponent development.

The toner of the invention can be applied to various developmentmethods. Specifically, those described in the first invention areavailable.

The toner of the invention can be applied to any machine of coronacharge (corotron system, scorotron system or the like) and contactcharge (charge roll system, charge brush system or the like). Further, amethod having no cleaning step, a blade method, a fur brush method, amagnetic brush method, a roller cleaning method and the like areavailable. A blade method and a method having no cleaning step arepreferable.

Next, the toner of the invention can be applied to any of an organicelectrophotographic photoreceptor (layered type or single-layer type)and an inorganic photoreceptor (amorphous silicon, amorphous selenium,selenium-based photoreceptor or germanium-based photoreceptor). It isespecially preferable to apply the same to an organicelectrophotographic photoreceptor and an inorganic photoreceptor usingamorphous silicon.

Moreover, the toner of the invention has characteristics that it can beapplied to (1) any of a reversible development process and a normaldevelopment process, (2) any of positively charged and negativelycharged toners, (3) any of monochromic and color printing machines, (4)any of an analog printing machine and a digital printing machine, and(5) a copying machine, a printer (a laser beam printer, a liquid crystalprinter or the like), a facsimile and a combined machine of these.

By the way, the softening temperature, the average molecular weight, thearomatic ring content and the hydrogenation rate of the aromatic ringwere measured by the following methods. Further, with respect to thesoftening temperature of the resin as the starting material alone inExamples to be described later, a value measured by a ring and ballmethod according to JIS K-2207 was described unless otherwiseinstructed.

(1) Softening Temperature

Measured by a ring and ball method according to JIS K-2207.

(2) Average Molecular Weight

A number-average molecular weight and a weight-average molecular weightcalculated as polystyrene were measured by gel permeation chromatography(GPC).

(3) Aromatic Ring Content

Analyzed by infrared absorption analysis. It was determined fromabsorbance at wavenumber of 700 cm⁻¹ using carbon disulfide as asolvent.

The invention is illustrated more specifically below by referring toExamples. However, the invention is not limited thereto.

I. First Invention

Synthesis Example I-1

A 1-liter autoclave was charged with 272 g of xylene as a solvent, andheated up to 260° C. in an atmosphere of a nitrogen gas. A mixture of170 g of dicyclopentadiene and 170 g of styrene was added over 2 hourswhile being stirred. And, while maintaining the temperature at 260° C.,the reaction was further conducted for 140 minutes.

An unreacted product and a low polymer were distilled off from thethus-obtained polymer solution to obtain resin [Ia].

This resin [Ia] was made of a structural unit derived fromdicyclopentadiene as component A and a structural unit derived fromstyrene as component B at a weight ratio of 50:50, and had properties, anumber-average molecular weight of 610, a heat-softening temperature of92° C., a bromine value of 60 g/100 g and an aromatic ring content of44%.

Subsequently, a 1-liter autoclave was charged with 250 g of resin [1a],3.0 g of a nickel-diatomaceous earth catalyst and 250 g of cyclohexaneas a solvent, and a hydrogenation reaction was conducted underconditions of a hydrogen pressure of 50 kg/cm²·G and a temperature of230° C. for 8 hours. After the completion of the reaction, the reactionproduct was cooled, and withdrawn. The catalyst was filtered off, andthe solvent was then distilled off to obtain resin [IIa].

This resin [IIa] was made of a structural unit derived fromdicyclopentadiene as component A and a structural unit derived fromstyrene as component B at a weight ratio of 50:50, and had properties, aheat-softening temperature of 125° C., a bromine value of 2.2 g/100 g,(bromine value of a hydrogenated resin/bromine value of anunhydrogenated resin)×100 of 3.7%, an aromatic ring content of 2.9% anda hydrogenation rate of an aromatic ring of 93%.

Incidentally, the softening temperature, the bromine value, the averagemolecular weight, the aromatic ring content and the hydrogenation rateof the aromatic ring were measured by the following methods.

(1) Softening Temperature

Measured by a ring and ball method according to JIS K-2207.

(2) Bromine Value

Measured according to JIS K-2605.

(3) Average Molecular Weight

A number-average molecular weight and a weight-average molecular weightcalculated as polystyrene were measured by gel permeation chromatography(GPC).

(4) Aromatic Ring Content

Analyzed by infrared absorption analysis. It was determined fromabsorbance at wavenumber of 700 cm⁻¹ using carbon disulfide as asolvent.

(5) Hydrogenation Rate of an Aromatic Ring

Calculated using the formula.

Hydrogenation rate (%) of an aromatic ring=[1−(aromatic ring content ofa hydrogenated resin/aromatic ring content of an unhydrogenatedresin)]×100

Synthesis Example I-2

A 1-liter autoclave was charged with 228 g of xylene as a solvent, andheated up to 260° C. in an atmosphere of a nitrogen gas. A mixture of190 g of dicyclopentadiene and 190 g of styrene was added over 2 hourswhile being stirred. And, while maintaining the temperature at 260° C.,the reaction was further conducted for 4 hours.

An unreacted product and a low polymer were distilled off from thethus-obtained polymer solution to obtain resin [Ib].

This resin [Ib] was made of a structural unit derived fromdicyclopentadiene as component A and a structural unit derived fromstyrene as component B at a weight ratio of 50:50, and had properties, anumber-average molecular weight of 690, a heat-softening temperature of110° C., a bromine value of 62 g/100 g and an aromatic ring content of46%.

Subsequently, a 1-liter autoclave was charged with 250 g of resin [1b],3.0 g of a nickel-diatomaceous earth catalyst and 250 g of cyclohexaneas a solvent, and a hydrogenation reaction was conducted underconditions of a hydrogen pressure of 40 kg/cm²·G and a temperature of230° C. for 5 hours. After the completion of the reaction, the reactionproduct was cooled, and withdrawn. The catalyst was filtered off, andthe solvent was then distilled off to obtain hydrogenated resin [IIb].

This resin [IIa] was made of a structural unit derived fromdicyclopentadiene as component A and a structural unit derived fromstyrene as component B at a weight ratio of 50:50, and had properties, aheat-softening temperature of 125° C., a bromine value of 4.4 g/100 g,(bromine value of a hydrogenated resin/bromine value of anunhydrogenated resin)×100 of 7.1%, an aromatic ring content of 24% and ahydrogenation rate of an aromatic ring of 48%.

EXAMPLE I-1

Hydrogenated resin [IIb] (71 g) obtained in Synthesis Example I-2 and 29g of polystyrene [IDEMITSU PS.HH made by Idemitsu Petrochemical Co.,Ltd.] having a weight-average molecular weight of 300,000 were mixed ina powdery state, and then biaxially kneaded with a LABOPLASTMILL havingan inner temperature of 140° C. to obtain a resin composition with acomposition ratio of both components A and B; [A/(A+B)]=0.71.

The thus-obtained resin composition was cooled, and then formed into asample for evaluation of brittleness with a thickness of 400 to 450 μmby hot-press molding.

Further, 100 parts by weight of the resulting kneaded product was mixedwith 2 parts by weight of a chromium-containing metallic dye [BONTRONS-34 made by Orient Chemical Industries, Co., Ltd.] and 7 parts byweight of carbon black [MA-100 made by Mitsubishi Chemical Corp.). Themixture was then kneaded with a LABOPLASTMILL having an innertemperature of 120° C., cooled, and then coarsely crushed using afeather mill. Subsequently, this was finely divided with a jet mill, andclassified with an air classifier to obtain toner particles having anaverage particle diameter of 10 μm.

To 100 parts by weight of the thus-obtained toner particles, 0.5 part byweight of titania fine particles [Idemitsu Titania made by IdemitsuPetrochemical Co., Ltd.] was added as conductive fine particles, andthey were mixed with a Henschel mixer to obtain a toner for developmentof an electrostatically charged image.

When this toner was evaluated as a toner for two-component developmentsystem, a polyethylene coat carrier [Idemitsu Carrier made by IdemitsuPetrochemical Co., Ltd.] was used as a carrier.

The thus-obtained toner particles and toner were evaluated with respectto the following items. The results are shown in Table I-I.

(1) Low-temperature Fixability (Lowest Fixing Temperature) and OffsetResistance

A commercial printer [FS-600 manufactured by Kyosera] was remodeled suchthat the temperature of the heating roll portion was variable, and usedas a tester for measuring the lowest fixing temperature and the offsetgenerating temperature. The lowest fixing temperature and the offsetgenerating temperature of the toner were measured using this tester.

(2) Charge Stability

One hundred grams of the above-obtained two-component developer (tonermixing ratio; 5%) was charged into a polyethylene container having aninternal volume of 100 ml, and stirred with a ball mill stand at 100 rpmfor 1 hour under conditions, namely, a high temperature and highhumidity [temperature 30° C.; humidity 80% (indicated at HH in TableI-1], a normal temperature and normal humidity [temperature 20° C.;humidity 50% (indicated at NN in Table I-1] and a low temperature andlow humidity [temperature 10° C.; humidity 20% (indicated at LL in TableI-1)]. Then, a charge amount was evaluated with a blow-off charge amountmeasuring device [TB-200 manufactured by Toshiba Chemical Corp.]

(3) Brittleness

The above-obtained sample for evaluation of brittleness was cut topieces having a size of 10 mm×10 mm. The test was conducted with aVickers hardness meter by changing the load to 100 gf, 200 gf, 300 gf,500 gf and 1,000 gf in order to observe a break state of the testpieces.

In this test, a break mark with a length of 2 mm or more which occurredin a test piece was defined as “break”, a break mark in which occurrenceof visible crack was observed was defined as “visible-crack”, and abreak mark which could be identified by only an optical microscope with100' magnification was defined as “microcrack”. Of these, brittlenesswas evaluated with a value of the lowest load under which “break”occurred.

(4) Thermal Properties

A glass transition temperature (indicated at Tg in Table I-1) and aheat-softening point (indicated at Tm in Table I-1) were measured.

EXAMPLE I-2

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 95 g, the amount of polystyrene used was changed to 5 g and aresin composition with a composition ratio of both components A and B;[A/(A+B)] =0.95 was provided. The results of evaluation of thelow-temperature fixability, the charge stability and the brittleness areshown in Table I-1.

EXAMPLE I-3

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 85 g, the polystyrene component was changed to 15 g ofpolystyrene [IDEMITSU PSHF 10 made by Idemitsu Petrochemical Co., Ltd.]having a weight-average molecular weight of 100,000 and a resincomposition with a composition ratio of both components A and B;[A/(A+B)]=0.85 was provided. The results of evaluation of thelow-temperature fixability, the charge stability and the brittleness areshown in Table I-1.

EXAMPLE I-4

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 71 g and the amount of the same compound as that in ExampleI-3 as a polystyrene component was changed to 29 g. The results ofevaluation of the low-temperature fixability, the charge stability andthe brittleness are shown in Table I-1.

EXAMPLE I-5

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 56 g, the amount of the same compound as that in Example I-3as a polystyrene component was changed to 44 g and a resin compositionwith a composition ratio of both components A and B; [A/(A+B)]=0.56 wasprovided. The results of evaluation of the low-temperature fixability,the charge stability and the brittleness are shown in Table I-1.

EXAMPLE I-6

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 71 g and a polystyrene component was changed to 29 g ofpolystyrene [HIMER SB-150 made by Sanyo Chemical Industries, Ltd.]having a weight-average molecular weight of 65,000. The results ofevaluation of the low-temperature fixability, the charge stability andthe brittleness are shown in Table I-1.

EXAMPLE I-7

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 71 g and a polystyrene component was changed to 29 g ofpolystyrene [HIMER SB-130 made by Sanyo Chemical Industries, Ltd.]having a molecular weight of 45,000. The results of evaluation of thelow-temperature fixability, the charge stability and the brittleness areshown in Table I-1.

EXAMPLE I-8

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as a starting component waschanged to 30 g, a polystyrene component was changed to 70 g ofpolystyrene [HIMER SB-130 made by Sanyo Chemical Industries, Ltd.]having a molecular weight of 45,000 and a resin composition with acomposition ratio of both components A and B; [A/(A+B)]=0.30 wasprovided. The results of evaluation of the low-temperature fixability,the charge stability and the brittleness are shown in Table I-1.

EXAMPLE I-9

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, 71g of hydrogenated resin [IIa] obtained in Synthesis Example I-2 was usedinstead of hydrogenated resin [IIb] used as a starting component and theamount of the same compound as that in Example I-3 as a polystyrenecomponent was changed to 29 g. The results of evaluation of thelow-temperature fixability, the charge stability and the brittleness areshown in Table I-1.

EXAMPLE I-10

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, 71g of a hydrogenated alicyclic saturated hydrocarbon resin [ARKON P-125made by Arakawa Chemical Industries, Ltd.] was used instead ofhydrogenated resin [IIb] used as a starting component and the amount ofthe same compound as that in Example I-3 as a polystyrene component waschanged to 29 g. The results of evaluation of the low-temperaturefixability, the charge stability and the brittleness are shown in TableI-1.

EXAMPLE I-11

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, 71g of a hydrogenated alicyclic saturated hydrocarbon resin [ARKON M-115made by Arakawa Chemical Industries, Ltd.] was used instead ofhydrogenated resin [IIb] used as a starting component and the amount ofthe same compound as that in Example I-3 as a polystyrene component waschanged to 29 g. The results of evaluation of the low-temperaturefixability, the charge stability and the brittleness are shown in TableI-1.

EXAMPLE I-12

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, 71g of a hydrogenated alicyclic saturated hydrocarbon resin [Escorez 5320made by Tonex Co., Ltd.] was used instead of hydrogenated resin [IIb]used as a starting component and the amount of the same compound as thatin Example I-3 as a polystyrene component was changed to 29 g. Theresults of evaluation of the low-temperature fixability, the chargestability and the brittleness are shown in Table I-1.

Comparative Example I-1

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as component A was changed to100 g and a polystyrene component as component B was not used. Theresults of evaluation of the low-temperature fixability, the chargestability and the brittleness are shown in Table I-1.

Comparative Example I-2

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1,hydrogenated resin [IIb] used as component A was not used and 100 g ofpolystyrene [IDEMITSU PS.HH 30 made by Idemitsu Petrochemical Co., Ltd.]having a weight-average molecular weight of 300,000 as used in ExampleI-1 was used. The results of evaluation of the low-temperaturefixability, the charge stability and the brittleness are shown in TableI-1.

Comparative Example I-3

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1,hydrogenated resin [IIb] used as component A was not used and 100 g ofpolystyrene [IDEMITSU PS.HF 10 made by Idemitsu Petrochemical Co., Ltd.]having a weight-average molecular weight of 100,000 as used in ExampleI-3 was used. The results of evaluation of the low-temperaturefixability, the charge stability and the brittleness are shown in TableI-1.

Comparative Example I-4

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 except that in Example I-1, theamount of hydrogenated resin [IIb] used as component A was changed to 20g, 80 g of polystyrene [IDEMITSU PS.HF 10 made by Idemitsu PetrochemicalCo., Ltd.] having a weight-average molecular weight of 100,000 as usedin Example I-3 was used and a resin composition with a composition ratioof both components A and B; [A/(A+B))=0.20 was provided. The results ofevaluation of the low-temperature fixability, the charge stability andthe brittleness are shown in Table I-1.

Comparative Example I-5

As a styrene-acrylic toner resin, the styrene-acrylic toner resindescribed in Nippon Setchaku Gakkaishi, vol. 23, No. 12, pp. 489-497(1987) was formed to obtain a sample for evaluation. In the thus-formedstyrene-acrylic toner resin, a ratio of a structural unit derived fromstyrene to a structural unit derived from butyl methacrylate was 65:35,a weight-average molecular weight was 86,000, and a glass transitiontemperature was 61° C. The results of evaluation of the low-temperaturefixability, the charge stability and the brittleness conducted on thesample for evaluation of brittleness and the sample of the toner areshown in Table I-1.

Comparative Example I-6

A sample for evaluation of brittleness and a sample of a toner wereproduced and evaluated as in Example I-1 using a polyester-based tonerresin obtained by tracing Example I-2 described in Japanese PatentLaid-Open No. 51,027/1986. The results of evaluation of thelow-temperature fixability, the charge stability and the brittleness areshown in Table I-1.

TABLE I-1 Lowest Offset Example fixing generating (Comparativetemperature temperature Charge amount (μC/g) Brittleness (times/10tests) Thermal properties Example) (° C.) (° C.) LL NN HH 300 gf 500 gf1,000 gf Tg (° C.) Tm (° C.) I-1 125 210< −26 −25 −25 0 2 8 65 120 I-2115 205  −25 −25 −24 0 4 10 60 105 I-3 115 210< −25 −25 −24 0 5 10 61105 I-4 120 210< −25 −25 −25 0 2 10 62 110 I-5 125 210< −25 −25 −24 0 09 64 115 I-6 115 210< −26 −25 −25 0 9 10 60 110 I-7 115 210< −25 −25 −240 10 10 60 105 I-8 130 210< −26 −26 −25 0 4 10 63 125 I-9 120 210< −25−25 −24 0 1 8 61 110  I-10 120 210< −25 −24 −24 0 3 8 62 110  I-11 115210< −26 −25 −25 1 10 10 61 105  I-12 120 210< −26 −25 −25 0 8 10 60 110(I-1) 120 160  −25 −25 −24 10 10 10 66 110 (I-2) 190 210< −25 −25 −24 00 0 100 160 (I-3) 175 210< −25 −25 −24 0 0 2 90 140 (I-4) 140 210< −26−25 −25 0 1 4 80 130 (I-5) 165 210< −26 −25 −22 0 7 10 66 150 (I-6) 140210< −28 −25 −21 0 8 10 64 130

II. Second Invention

EXAMPLE II-1

[1] Production of a Resin Composition

(a) Polystyrene [HF-10 made by Idemitsu Petrochemical Co., Ltd., 4.8 kg]having a weight-average molecular weight of 210,000 was used as apolystyrene-type polymer as component (a). Further, a petroleumresin-based polymer used as component (b) is as follows. That is, whenthe petroleum resin-based polymer as component (b) formed a resincomposition with the polystyrene-type polymer as component (a) at aweight ratio of 1:1, total light transmission measured according to JISK 7105 on a film-like molded product of the resin composition having athickness of 3 mm was 91% of a quantity of incident light, and hazemeasured according to JIS K 7105 was 1.1%. Further, 5.2 kg of anaromatic petrochemical resin [FTR-8120 made by Mitsui Chemicals, Inc.]having a softening temperature of 120° C. and a Hazen color number of 50as measured according to JIS K 6901 and using a purified aromaticcompound component with a specific structure as a starting material wasused.

Both of these components (a) and (b) were mixed in a pelletized state,fed to a twin-screw extruder (Labotex manufactured by The Japan SteelWorks, Ltd.; screw diameter·32 mm], and melt-kneaded at a resintemperature of 160° C. to obtain a resin composition.

[2] Evaluation of a Resin Composition

(A) Measurement of Total Light Transmission and Haze

The resin composition (32 g) obtained in (1) was subjected to hot-pressmolding to produce a test piece for measuring total light transmission.In the hot-press molding, a hot press manufactured by Shimadzu RikaKikai K.K. and a mold having a size of 100 mm×100 mm×3 mm were used. Themolding was conducted under conditions of a mold temperature of 140° C.,a press pressure of 50 to 70 kgf/cm² and a molding time of 10 minutes.

Total light transmission and haze were measured according to JIS K 7105with a fully automatic direct reading haze computer [Model HGM-2DPmanufactured by SUGA TEST INSTRUMENTS Co., Ltd.] using the thus-obtainedfilm-like test pieces 3 mm in thickness.

(B) Measurement of Weight Loss at 150° C.

With respect to the resin composition obtained in (1), the change inweight was observed in air with a thermogravimetry device [TG/DTA 300manufactured by Seiko Instruments & Electronics Ltd.] when a temperaturewas raised from room temperature to 600° C. at a rate of rise of 10°C./min. A weight loss ratio (percentage) of an amount of change inweight at 150  C. to initial weight was measured.

(C) Measurement of a Glass Transition Temperature

With respect to the resin composition obtained in (1), an extrapolationglass transition starting temperature in second heating was measuredaccording to JIS K 7121 using a differential scanning calorimeter[manufactured by Seiko Instruments & Electronics Ltd.] by increasing thetemperature at a rate of rise of 10° C./10 min.

(D) Measurement of a Softening Temperature

The resin composition obtained in (1) was measured with a flow testersoftening temperature measuring device manufactured by Shimadzu RikaKikai K.K. The measurement conditions were that load was 20 kgf, anorifice diameter was 1.0 mm, a length was 1.0 mm, a plunger area was 1.0cm², a sample amount was 1.0 g, a starting temperature was 80° C., arate of rise was 6.0° C./min and preheating was conducted for 200seconds. And, an outflow starting temperature and a ½ outflowtemperature were read from a measurement time-temperature chart and ameasurement time-piston displacement chart.

The results of evaluation are shown in Table II-1.

[3] Production of a Toner for Development of an ElectrostaticallyCharged Image

One hundred parts by weight of the resin composition obtained in (1) wasmixed with 2 parts by weight of a chromium-containing metallic dye[BONTRON S-34 made by Orient Chemical Industries, Co., Ltd.], 5 parts byweight of polypropylene wax [Biscol 550 made by Sanyo ChemicalIndustries, Ltd.] as wax and 7 parts by weight of carbon black [MA-100made by Mitsubishi Chemical Corp.) as a colorant. The mixture waskneaded at a resin temperature of 160° C. with a LABOPLASTMILL.

This kneaded product was then coarsely crushed using a feather mill.And, this coarsely crushed product was pulverized with a jet mill, andclassified with an air classifier to obtain toner particles having avolume-average particle diameter of 10 μm.

To 100 parts by weight of the thus-obtained toner particles, 0.5 part byweight of titania fine particles [Idemitsu Titania made by IdemitsuPetrochemical Co., Ltd.] was then added as a fluidity imparting agent,and they were mixed with a Henschel mixer to obtain a toner fordevelopment of an electrostatically charged image.

When this toner was evaluated as a toner for two-component developmentsystem, a polyethylene coat carrier [Idemitsu Carrier made by IdemitsuPetrochemical Co., Ltd.] was used as a carrier.

[4] Evaluation of a Toner for Development of an ElectrostaticallyCharged Image

(A) Evaluation of Mechanical Strength

The suitability of the mechanical strength of the toner was evaluatedfrom the pulverization pressure with the jet mill in the pulverizationand the amount of the finely divided component with the particlediameter of less than 5 μm which was removed with an air classifier in(2). When the jet mill pulverization pressure had to be increased, themechanical strength was estimated to be “too strong”, and when theamount of the finely divided component was large, the mechanicalstrength was estimated to be “too weak”.

(B) Evaluation of Low-temperature Fixability and Offset Resistance

A commercial printer [FS-600 manufactured by Kyosera] was remodeled suchthat the temperature of the heating roll portion was variable, and usedas a tester for measuring the lowest fixing temperature and the offsetgenerating temperature. The lowest fixing temperature and the offsetgenerating temperature of the toner were measured using this tester.

With respect to the low-temperature fixability herein, when the lowestfixing temperature was 145° C. or less, it was estimated to be good(expressed by mark in Table II-1), and when the lowest fixingtemperature was 146° C. or more, it was estimated to be bad (expressedby mark x in Table II-1).

Further, with respect to the offset resistance, when an offsetgenerating temperature was 210° C. or more, it was estimated to be good(expressed by mark in Table II-1), and when the offset generatingtemperature was 209° C. or less, it was estimated to be bad (expressedby mark x in Table II-1).

(C) Evaluation of an Odor

A degree of an odor given off was measured in the evaluation of thelow-temperature fixability. When there was no odor at all, it wasestimated to be excellent (expressed by mark ⊚ in Table II-1). Whenfixing was conducted with a fixing machine in an uncovered state and aslight odor was smelled but no odor was smelled in a common use state,it was estimated to be good (expressed by mark ∘ in Table II-1). When anodor was smelled in fixation, it was estimated to be bad (expressed bymark x in Table II-1).

(D) Evaluation of Transparency

When color reproducibility of transmitted light was excellent in using atoner as a color toner, transparency was estimated to be excellent(expressed by mark ⊚ in Table II-1). When scattering of transmittedlight less occurred with no problem in the use as a color toner but animage was slightly dark, transparency was estimated to be good(expressed by mark ∘ in Table II-1). When an image was cloudy or coloredwith poor color reproducibility, transparency was estimated to be bad(expressed by mark x in Table II-1).

EXAMPLE II-2

Example II-1 was repeated except that in Example II-1, the amount ofpolystyrene used as component (a) was changed to 1.5 kg and the amountof the petroleum resin used as component (b) was changed to 8.5 kg.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-3

In Example II-1, the amount of polystyrene used as component (a) waschanged to 6.5 kg and the following resin was used as the petroleumresin, component (b). That is, when the resin formed a resin compositionwith the polystyrene-type polymer as component (a) at a weight ratio of1:1, total light transmission measured according to JIS K 7105 on afilm-like molded product of the resin composition having a thickness of3 mm was 93% of a quantity of incident light, and haze measuredaccording to JIS K 7105 was 1.3%. Further, Example II-1 was repeatedexcept that the aromatic petrochemical resin was changed to 3.5 kg of anaromatic petrochemical resin [FTR-8100 made by Mitsui Chemicals, Inc.]having a softening temperature of 120° C. and a Hazen color number of 50and using a purified aromatic compound component with a specificstructure as a starting material was used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-4

Example II-1 was repeated except that in Example II-1, 3.0 kg ofpolystyrene [UP-305 made by Idemitsu Petrochemical Co., Ltd.] having aweight-average molecular weight of 380,000 was used instead ofpolystyrene used as component (a) and the amount of the petroleum resinused as component (b) was changed to 7.0 kg.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-5

Example II-1 was repeated except that in Example II-1, a styrene-butylmethacrylate copolymer resin obtained by copolymerizing styrene andbutyl methacrylate as monomers at a molar ratio of 75:25 and having aweight-average molecular weight of 110,000 was used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-6

In Example II-1, the following resin was used instead of the petroleumresin as component (b). That is, when the resin formed a resincomposition with the polystyrene-type polymer as component (a) at aweight ratio of 1:1, total light transmission measured according to JISK 7105 on a film-like molded product of the resin composition having athickness of 3 mm was 86% of a quantity of incident light, and hazemeasured according to JIS K 7105 was 5.3%. Further, Example II-1 wasrepeated except that an ester group-containingpolydicyclopentadiene-based petroleum resin [Quintone 1500 made byNippon Zeon Co., Ltd.] having a softening temperature of 100° C., asaponification value of 175 mg KOH/g and a Gardner color number of 3 asmeasured in a molten state according to JIS K 5400 was used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-7

The petroleum resin as component (b) was formed as follows.

Xylene (154 g) was fed as a solvent to a nitrogen-purged 1-literpolymerization reactor fitted with a stirrer. To this was added amixture of 269 g of cyclopentadiene and 269 g of styrene successivelyover 2 hours while being heat-stirred at 230° C. Then, the reactionsolution was heated to 260° C. over 105 minutes, and the reaction wasconducted for 4 hours.

After the completion of the reaction, the purified reaction solution waswithdrawn, and an unreacted monomer and xylene were removed at 200° C.and 1 mmHg using a rotary evaporator to obtain 510 g of a copolymer ofcyclopentadiene and styrene.

Subsequently, a nitrogen-purged 300-milliliter polymerization reactorfitted with a stirrer was charged with 75 g of cyclohexane as a solvent,75 g of the copolymer of cyclopentadiene and styrene and 4.0 g of asilin-alumina catalyst supporting 0.5% by weight of platinum. A hydrogengas was introduced therein at a pressure of 4 MPa, and a hydrogenationreaction was conducted at 150° C. over 2 hours.

The thus-obtained hydrogenated cyclopentadiene-styrene copolymer was asfollows. That is, when the copolymer formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was90.3% of a quantity of incident light, and haze measured according toJIS K 7105 was 4.1%. Further, a softening temperature was 120° C., anaromatic component content was 43% by weight, a bromine value was 14g/100 g, and a Gardener color number was 3.

Example II-1 was repeated except that component (a) in Example II-1 andthe above-obtained petroleum resin as component (b) were used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-8

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was74% of a quantity of incident light, and haze measured according to JISK 7105 was 3.2%. Further, Example II-1 was repeated except that anaromatic petroleum resin [Petrotack 90 made by Tosoh Corp.] having asoftening temperature of 90° C. and a Gardener color number of 6 wasused.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-9

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was72% of a quantity of incident light, and haze measured according to JISK 7105 was 6.1%. Further, Example II-1 was repeated except that anaromatic petroleum resin [Petcoal 120 made by Tosoh Corp.] having asoftening temperature of 120° C. and a Gardener color number of 7 wasused.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-10

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was66.2% of a quantity of incident light, and haze measured according toJIS K 7105 was 4.9%. Further, Example II-1 was repeated except that anaromatic petroleum resin [HIRESIN #90 made by Toho Kagaku Kogyo K.K.]having a softening temperature of 100° C. and a Gardener color number of8 was used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-11

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was91% of a quantity of incident light, and haze measured according to JISK 7105 was 1.2%. Further, Example II-1 was repeated except that apetroleum resin obtained by copolymerizing α-methylstyrene andisopropenyltoluene as monomers at a molar ratio of 1:1 as describedbelow and having a softening temperature of 96° C. was used.

A 500-milliliter flask fitted with a thermometer and a stirrer wascharged with 50 g of α-methylstyrene, 50 g of isopropenyltoluene and 200g of toluene as a solvent. The temperature was maintained at 0° C. whilestirring the mixture, and 1.0 g of a boron trifluoride phenol complexwas added dropwise thereto for 20 minutes. Further, the reaction wasconducted at 0° C. for 2 hours with stirring, and 50 g of a sodiumhydroxide aqueous solution having a concentration of 2% by weight wasthen added to decompose the catalyst. The resulting reaction solutionwas washed with water, the solvent was distilled off, and an unreactedmonomer and a low polymer were removed at 200° C. under reduced pressureof 5 mmHg to obtain an aromatic petroleum resin.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-12

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was87% of a quantity of incident light, and haze measured according to JISK 7105 was 4.3%. Further, Example II-1 was repeated except that apetroleum resin obtained by copolymerizing indene and vinyltoluene asmonomers at a molar ratio of 1:3 as described below and having asoftening temperature of 100° C. was used.

A 500-milliliter flask fitted with a thermometer and a stirrer wascharged with 25 g of indene, 75 g of vinyltoluene and 200 g of tolueneas a solvent. The temperature was maintained at 0° C. while stirring themixture, and 1.0 g of a boron trifluoride phenol complex was addeddropwise thereto for 20 minutes. Further, the reaction was conducted at0° C. for 2 hours with stirring, and 50 g of a sodium hydroxide aqueoussolution having a concentration of 2% by weight was then added todecompose the catalyst. The resulting reaction solution was washed withwater, the solvent was distilled off, and an unreacted monomer and a lowpolymer were removed at 200° C. under reduced pressure of 5 mmHg toobtain an aromatic petroleum resin.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

EXAMPLE II-13

The following resin was used instead of the petroleum resin used ascomponent (b) in Example II-1. That is, when the resin formed a resincomposition with the polystyrene-type polymer as component (a) at aweight ratio of 1:1, total light transmission measured according to JISK 7105 on a film-like molded product of the resin composition having athickness of 3 mm was 87% of a quantity of incident light, and hazemeasured according to JIS K 7105 was 2.8%. Further, it is a hydroxylgroup-containing dicyclopentadiene polymer-based petroleum resin(“Quintone 1700” made by Nippon Zeon Co., Ltd., softening temperature100° C.) having a hydroxyl value of 220 mg KOH/g.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

Comparative Example II-1

A petroleum resin as component (b) was produced as follows.

An autoclave having an internal volume of 1 liter was charged with 228 gof xylene, and heated up to 260° C. in an atmosphere of a nitrogen gas.A mixture of 190 g of dicyclopentadiene and 190 g of styrene was addedover 2 hours while being stirred. The reaction was further conducted atthe same temperature for 4 hours. An unreacted monomer, a low polymerand the solvent were removed from the resulting polymer solution toobtain a dicyclopentadiene-styrene copolymer having a number-averagemolecular weight of 690, a softening temperature of 110° C., a brominevalue of 62 g/100 g and an aromatic ring content of 46% by weight.

Subsequently, an autoclave having an internal volume of 1 liter wascharged with 250 g of cyclohexane as a solvent, 250 g of theabove-obtained dicyclopentadiene-styrene copolymer and 3.0 g of anickel-diatomaceous earth catalyst, and a hydrogenation reaction wasconducted at a temperature of 230° C. and a hydrogen gas pressure of 40kg/cm²G over 5 hours. Then, the reaction product was filtered to removethe catalyst, and the solvent was distilled off to obtain a hydrogenateddicyclopentadiene-styrene copolymer. When this copolymer formed a resincomposition with the polystyrene-type polymer as component (a) at aweight ratio of 1:1, total light transmission measured according to JISK 7105 on a film-like molded product of the resin composition having athickness of 3 mm was 48% of a quantity of incident light, and hazemeasured according to JIS K 7105 was 92%. The softening temperature was125° C., the bromine value was 4.4 g/100 g, the aromatic ring contentwas 24% by weight, and the hydrogenation rate of the aromatic ring was48%.

Example II-1 was repeated except that polystyrene as component (a) inExample II-1 and the above-obtained petroleum resin as component (b)were used.

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table II-1.

Comparative Example II-2

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was48% of a quantity of incident light, and haze measured according to JISK 7105 was 3.1%. Further, the resin composition was produced as inExample II-1 except that a petroleum resin [Petorosin #120 made byMitsui Chemicals, Inc.] having a softening temperature of 120° C. and aGardener color number of 11 as measured in a molten condition accordingto JIS K 5400 was used. The resulting resin composition was colored, andthe total light transmission was as low as 47.9%. The results ofevaluation of the resin composition obtained herein and a toner producedas in Example II-1 using the same are shown in Table II-1.

Comparative Example II-3

The following resin was used as the petroleum resin, component (b)instead of the petroleum resin used as component (b) in Example II-1.That is, when the resin formed a resin composition with thepolystyrene-type polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm was54% of a quantity of incident light, and haze measured according to JISK 7105 was 6.3%. Further, the resin composition was produced as inExample II-1 except that a petroleum resin [NEOPOLYMER 120 made byNisseki Kagaku Kogyo K.K.] having a softening temperature of 120° C. anda Gardener color number of 4 as measured in a toluene solution having aconcentration of 2 g/25 ml according to JIS K 5400 was used. Theresulting resin composition was colored, and the total lighttransmission was as low as 53.5%. The results of evaluation of the resincomposition obtained herein and a toner produced as in Example II-1using the same are shown in Table II-1.

TABLE II-1 Resin composition Toner Glass Outflow Low- Ex. Total lightWeight transition starting ½ outflow temperature Offset MechanicalTrans- (Comp. Ex.) transmission Haze loss temperature temperaturetemperature fixability resistance strength Odor parency II-1 90.6 1.10.6 68 121 146 ∘ ∘ suitable ⊚ ⊚ II-2 90.6 6.9 0.6 63 111 136 ∘ ∘suitable ⊚ ⊚ II-3 90.3 1.3 0.7 68 116 140 ∘ ∘ suitable ⊚ ⊚ II-4 90.7 1.10.6 71 124 147 ∘ ∘ suitable ⊚ ⊚ II-5 87.6 6.1 0.6 63 127 146 ∘ ∘suitable ⊚ ⊚ II-6 86.0 5.3 0.7 62 112 136 ∘ ∘ suitable ⊚ ⊚ II-7 90.3 4.10.6 64 119 145 ∘ ∘ suitable ⊚ ⊚ II-8 73.7 3.2 1.0 60 110 136 ∘ ∘suitable ∘ ∘ II-9 72.1 6.1 1.0 71 124 147 ∘ ∘ suitable ∘ ∘  II-10 66.24.9 1.0 58 110 137 ∘ ∘ suitable ∘ ∘  II-11 90.8 1.2 0.7 60 110 135 ∘ ∘suitable ⊚ ⊚  II-12 87.2 4.3 0.7 60 111 135 ∘ ∘ suitable ⊚ ⊚  II-13 85.14.6 0.7 62 112 136 ∘ ∘ suitable ⊚ ⊚ (II-1) 47.6 91.5 0.7 64 123 147 ∘ ∘suitable ⊚ x (II-2) 47.9 3.1 1.5 71 121 147 ∘ ∘ suitable x x (II-3) 53.56.3 1.7 71 124 147 ∘ ∘ suitable x x

III. Third Invention

EXAMPLE III-1

[1] Production of a Resin Composition

Polystyrene [HF-10 made by Idemitsu Petrochemical Co., Ltd., 4.5 kg]having a weight-average molecular weight of 210,000 was used as apolystyrene-type polymer, component (B). Further, 5.5 kg of a terpenephenol resin [Mighty Ace G125 made by Yasuhara Chemical K.K.] usingdipentene as a starting material and having a softening temperature of120° C. was used as a terpene resin, component (A).

After both these components (A) and (B) were mixed in a pelletizedstate, the mixture was fed to a twin-screw extruder [Labotexmanufactured by The Japan Steel Works, Ltd.; screw diameter·30 mm], andmelt-kneaded at a resin temperature of 160° C. to obtain a resincomposition.

[2] Evaluation of a Resin Composition

(A) Measurement of a Glass Transition Temperature

The resin composition obtained in (1) was measured in the same manner asdescribed in the second invention using a differential scanningcalorimeter [manufactured by Seiko Instruments & Electronics Ltd.].

(B) Measurement of a Softening Temperature

The resin composition obtained in (1) was measured in the same manner asdescribed in the second invention. The results of evaluation thereof areshown in Table III-1.

[3] Production of a Toner for Development of an ElectrostaticallyCharged Image

With respect to the resin composition obtained in (1), toner particleshaving a volume-average particle diameter of 10 μm were obtained in thesame manner as described in the second invention.

To 100 parts by weight of the thus-obtained toner particles, 0.5 part byweight of titania fine particles [Idemitsu Titania made by IdemitsuPetrochemical Co., Ltd.] was then added as a fluidity imparting agent,and they were mixed with a Henschel Mixer to obtain a toner fordevelopment of an electrostatically charged image.

When this toner was evaluated as a toner for two-component developmentsystem, a polyethylene coat carrier [Idemitsu Carrier made by IdemitsuPetrochemical Co., Ltd.] was used as a carrier.

[4] Evaluation of a Toner for Development of an ElectrostaticallyCharged Image

(A) Evaluation of Mechanical Strength

Evaluated in the same manner as described in the second invention.

(B) Low-temperature Fixability and Offset Resistance

Evaluated in the same manner as described in the second invention.

EXAMPLE III-2

Example III-1 was repeated except that a hydrogenated aromatic modifiedterpene resin [Clearon K-110 made by Yasuhara Chemical K.K.] having asoftening temperature of 110° C. was used as a terpene resin, component(A)(a).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-3

Example III-1 was repeated except that an aromatic modified terpeneresin [YS Resin TO-115 made by Yasuhara Chemical K.K.] having asoftening temperature of 115° C. was used as a terpene resin, component(A)(a).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-4

Example III-1 was repeated except that a terpene phenol resin [YSPolystar T115 made by Yasuhara Chemical K.K.] using α-pinene as astarting material and having a softening temperature of 115° C. was usedas a terpene resin, component (A)(a).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-5

Example III-1 was repeated except that a terpene phenol resin [YS ResinPx-1000 made by Yasuhara Chemical K.K.] using β-pinene and dipentene asstarting materials and having a softening temperature of 100° C. wasused as a terpene resin, component (A)(a).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-6

Example III-1 was repeated except that the terpene resin used ascomponent (A)(a) was replaced with an ester gum [Pencel made by ArakawaChemical Industries, Ltd.] having a softening temperature of 115° C. asa rosin resin, component (A)(b).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-7

Example III-1 was repeated except that the terpene resin used ascomponent (A)(a) was replaced with a rosin-maleic acid resin [acid value100] having a softening temperature of 113° C. as a rosin resin,component (A)(b).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-8

Example III-1 was repeated except that the terpene resin used ascomponent (A)(a) was replaced with a hydrogenated aromatic petroleumresin [Regalite S5100 made by Hercules] having a softening temperatureof 100° C. as a hydrogenated aromatic petroleum resin, component (A)(c).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-9

Example III-1 was repeated except that the terpene resin used ascomponent (A)(a) was replaced with a hydrogenated aromatic petroleumresin [ARKON M100 made by Arakawa Chemical Industries, Ltd.] having asoftening temperature of 100° C. as a hydrogenated aromatic petroleumresin, component (A)(c).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-10

Example III-1 was repeated except that polystyrene used as component (B)in Example III-1 was replaced with a styrene-butyl methacrylatecopolymer resin obtained by copolymerizing styrene and butylmethacrylate as monomers at a molar ratio of 75:25 and having aweight-average molecular weight of 110,000 and the terpene resin used ascomponent (A)(a) was replaced with a hydrogenated aromatic petroleumresin [ARKON M100 made by Arakawa Chemical Industries, Ltd.] having asoftening temperature of 100° C. as a hydrogenated aromatic petroleumresin, component (A)(c).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

EXAMPLE III-11

Example III-1 was repeated except that in Example III-1, polystyreneused as component (B) was replaced with 3.0 kg of a polyester resin(glass transition temperature=64° C., softening point=130° C.) formed bythe method described in Example III-1 of Japanese Patent Laid-Open No.225,520/1990 and the terpene resin used as component (A)(a) was replacedwith a hydrogenated aromatic petroleum resin [Regalite S5100 made byHercules] having a softening temperature of 100° C. as a hydrogenatedaromatic petroleum resin, component (A)(c).

The results of evaluation of the thus-obtained resin composition andtoner are shown in Table III-1.

Comparative Example III-1

A toner was produced as in Example III-1 except that 10 kg of thestyrene-acrylic resin used in Example III-10 was used as a binder resin.

The results of evaluation of the resin used herein and the resultingtoner are shown in Table III-1.

Comparative Example III-2

A toner was produced as in Example III-1 except that 10 kg of thepolyester resin used in Example III-11 was used as a binder resin.

The results of evaluation of the resin used herein and the resultingtoner are shown in Table III-1.

TABLE III-1 Resin composition Glass Outflow ½ Toner transition startingoutflow Low- Ex. tem- tem- tem- tem- Offset Mechan- (Comp. peratureperature perature perature resis- ical Ex.) (° C.) (° C.) (° C.)fixability tance strength III-1 68 120 144 ∘ ∘ suitable III-2 62 117 139∘ ∘ suitable III-3 59 122 142 ∘ ∘ suitable III-4 63 118 142 ∘ ∘ suitableIII-5 60 117 140 ∘ ∘ suitable III-6 61 116 137 ∘ ∘ suitable III-7 58 117139 ∘ ∘ suitable III-8 62 115 136 ∘ ∘ suitable III-9 63 115 137 ∘ ∘suitable III-10 58 115 137 ∘ ∘ suitable III-11 57 106 127 ∘ ∘ suitable(III-1) 65 120 150 x ∘ suitable (III-2) 64 107 133 ∘ ∘ too strong

INDUSTRIAL APPLICABILITY

As has been thus far described, the toner binder resin of the firstinvention is a toner binder resin for development of anelectrostatically charged image which is used for developing anelectrostatic latent image formed in an electrophotographic method, anelectrostatic recording method, an electrostatic printing method or thelike. And, a toner obtained by using the same has excellent effects thatthe low-temperature fixability is excellent, the mechanical strengthcapable of enduring the practical use as a toner is provided and theenvironmental dependence in charging a toner is low.

Further, the resin composition of the second invention is excellent intransparency and suited for use in the toner binder resin fordevelopment of an electrostatically charged image which is used fordeveloping an electrostatic latent image formed in anelectrophotographic method, an electrostatic recording method, anelectrostatic printing method or the like. And, the toner fordevelopment of an electrostatically charged image obtained byincorporating suitable amounts of a coloring material, a charge controlagent and wax in this resin composition is excellent in low-temperaturefixability, has suitable mechanical strength and is substantiallytransparent. Accordingly, color reproducibility of transmitted light isexcellent when it is used as a color toner.

Moreover, the resin composition of the third invention is excellent inlow-temperature fixability, has suitable mechanical strength as a tonerresin, and is suited for use in a toner binder resin for development ofan electrostatically charged image which is used for developing anelectrostatic latent image formed in an electrophotographic method, anelectrostatic recording method, an electrostatic printing method or thelike. And, the toner for development of an electrostatically chargedimage obtained by incorporating suitable amounts of a coloring material,a charge control agent and wax in this resin composition is excellent inlow-temperature fixability without decreasing grindability in the tonerproduction.

What is claimed is:
 1. A resin composition comprising a polymer blendwhich comprises (a) 10 to 65% by weight of a polystyrene-based polymercomponent and (b) 35 to 90% by weight of the petroleum resin-basedpolymer component wherein the petroleum resin-based polymer component(b) is selected based on a criteria that when the petroleum resin-basedpolymer forms a resin composition with the polystyrene-based polymer ata weight ratio of 1:1, total light transmission measured according toJIS K 7105 on a film-like molded product of the resin composition havinga thickness of 3 mm is 60% or more of a quantity of incident light, andhaze measured according to JIS K 7105 is 40% or less.
 2. The resincomposition as claimed in claim 1, wherein the petroleum resin-basedpolymer component (b) is selected based on a criteria that when thepetroleum resin-based polymer forms a resin composition with thepolystyrene-based polymer as component (a) at a weight ratio of 1:1,total light transmission measured according to JIS K 7105 on a film-likemolded product of the resin composition having a thickness of 3 mm is60% or more of a quantity of incident light.
 3. The resin composition asclaimed in claim 1, which comprises (a) 10 to 49% by weight of thepolystyrene-based polymer component and (b) 51 to 90% by weight of thepetroleum resin-based polymer component.
 4. The resin composition asclaimed in claim 1, wherein the polystyrene-based polymer component (a)is a styrene homopolymer and/or a styrene-unsaturated carboxylic estercopolymer in which a ratio of a content of a styrene unit to a contentof an unsaturated carboxylic ester unit is 1.1 or more in terms of amolar ratio.
 5. The resin composition as claimed in claim 1, wherein thepetroleum resin-based polymer component (b) is a petroleum resin-basedpolymer having a softening temperature of 130° C. or less.
 6. The resincomposition as claimed in claim 1, wherein the petroleum resin-basedpolymer component (b) is an aromatic petroleum resin.
 7. The resincomposition as claimed in claim 1, wherein the petroleum resin-basedpolymer component (b) is a polymer or a copolymer of one or moreselected from the group consisting of vinyltoluene, α-methylstyrene,isopropenyltoluene and indene.
 8. The resin composition as claimed inclaim 1, wherein the petroleum resin-based polymer component (b) is anester group-containing dicyclopentadiene polymer-based petroleum resinhaving a saponification value of 10 to 400 mg KOH/g.
 9. The resincomposition as claimed in claim 1, wherein the petroleum resin-basedpolymer component (b) is a hydroxyl group-containing dicyclopentadienepolymer-based petroleum resin having a hydroxyl value of 10 to 400 mgKOH/g.
 10. The resin composition as claimed in claim 1, wherein thepetroleum resin-based polymer component (b) is one in which a part orthe whole of the unsaturated bond and/or the aromatic ring ishydrogenated.
 11. The resin composition as claimed in claim 1, whereinthe petroleum resin-based polymer component (b) is a petroleumresin-based polymer having weight loss of 1% by weight or less asmeasured at 150° C. by thermogravimetry.